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Godshall GF, Rau DA, Williams CB, Moore RB. Additive Manufacturing of Poly(phenylene Sulfide) Aerogels via Simultaneous Material Extrusion and Thermally Induced Phase Separation. Adv Mater 2023:e2307881. [PMID: 38009658 DOI: 10.1002/adma.202307881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/30/2023] [Indexed: 11/29/2023]
Abstract
Additive manufacturing (AM) of aerogels increases the achievable geometric complexity, and affords fabrication of hierarchically porous structures. In this work, a custom heated material extrusion (MEX) device prints aerogels of poly(phenylene sulfide) (PPS), an engineering thermoplastic, via in situ thermally induced phase separation (TIPS). First, pre-prepared solid gel inks are dissolved at high temperatures in the heated extruder barrel to form a homogeneous polymer solution. Solutions are then extruded onto a room-temperature substrate, where printed roads maintain their bead shape and rapidly solidify via TIPS, thus enabling layer-wise MEX AM. Printed gels are converted to aerogels via postprocessing solvent exchange and freeze-drying. This work explores the effect of ink composition on printed aerogel morphology and thermomechanical properties. Scanning electron microscopy micrographs reveal complex hierarchical microstructures that are compositionally dependent. Printed aerogels demonstrate tailorable porosities (50.0-74.8%) and densities (0.345-0.684 g cm-3 ), which align well with cast aerogel analogs. Differential scanning calorimetry thermograms indicate printed aerogels are highly crystalline (≈43%), suggesting that printing does not inhibit the solidification process occurring during TIPS (polymer crystallization). Uniaxial compression testing reveals that compositionally dependent microstructure governs aerogel mechanical behavior, with compressive moduli ranging from 33.0 to 106.5 MPa.
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Affiliation(s)
- Garrett F Godshall
- Department of Chemistry, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Daniel A Rau
- Department of Mechanical Engineering, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Christopher B Williams
- Department of Mechanical Engineering, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Robert B Moore
- Department of Chemistry, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
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2
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Weyhrich CW, Will JW, Nayyar G, Westover CC, Patterson S, Arrington CB, Williams CB, Long TE. Temporally Stable Supramolecular Polymeric Salts Enabling High-Performance 3D All-Aromatic Polyimide Lattices. Small 2023; 19:e2303188. [PMID: 37165302 DOI: 10.1002/smll.202303188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 04/28/2023] [Indexed: 05/12/2023]
Abstract
Vat photopolymerization (VP) Additive Manufacturing (AM), in which UV light is selectively applied to cure photo-active polymers into complex geometries with micron-scale resolution, has a limited selection of aliphatic thermoset materials that exhibit relatively poor thermal performance. Ring-opening dianhydrides with acrylate-containing nucleophiles yielded diacrylate ester-dicarboxylic acids that enabled photo-active polyimide (PI) precursors, termed polysalts, upon neutralization with an aromatic diamine in solution. In situ FTIR spectroscopy coupled with a solution and photo-rheological measurements revealed a previously unknown time-dependent instability of 4,4'-oxydianiline (ODA) polysalts due to an aza-Michael addition. Replacement of the electron-donating ether-containing diamine with an electron withdrawing sulfone-containing monomer, e.g., 4,4'-diaminodiphenyl sulfone (DDS), prohibited the aza-Michael addition of the aromatic amine to the activated acrylate double bond. Novel DDS polysalt photocurable solutions are similarly analyzed and validated long-term stability, which enabled reproducible printing of polyimide organogel intermediates. Subsequent VP AM afforded 3-dimensional (3D) structures of intricate complexity and excellent surface finish, as demonstrated with scanning electron microscopy. In addition, the novel PMDA-HEA/DDS solution enabled the production of the first beam latticed architecture comprised of all-aromatic polyimide. The versatility of a polysalt platform for multi-material printing is further demonstrated by printing parts with alternating polysalt compositions.
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Affiliation(s)
- Cody W Weyhrich
- School of Molecular Sciences and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, AZ, 85281, USA
| | - John W Will
- Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Garvit Nayyar
- School of Engineering of Matter, Transport, and Energy and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, AZ, 85281, USA
| | - Clarissa C Westover
- Department of Materials Science and Engineering and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, AZ, 85281, USA
| | - Steven Patterson
- Honeywell Federal Manufacturing and Technologies, LLC, Kansas City, MO, 64147, USA
| | - Clay B Arrington
- School of Molecular Sciences and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, AZ, 85281, USA
| | - Christopher B Williams
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Timothy E Long
- School of Molecular Sciences and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, AZ, 85281, USA
- School of Engineering of Matter, Transport, and Energy and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, AZ, 85281, USA
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Weyhrich CW, Will JW, Heifferon KV, Brown JR, Arrington CB, Meenakshisundaram V, Williams CB, Long TE. 3D‐Printing of Poly(arylene ether sulfone)s: Functional High‐Performance Polymers for Vat Photopolymerization. MACROMOL CHEM PHYS 2022. [DOI: 10.1002/macp.202200240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Cody W. Weyhrich
- School of Molecular Sciences and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing Arizona State University Tempe AZ 85281 USA
| | - John W. Will
- Macromolecules Innovation Institute Department of Material Science and Engineering Virginia Tech Blacksburg VA 24061 USA
| | - Katherine V. Heifferon
- Macromolecules Innovation Institute Department of Chemistry Virginia Tech Blacksburg VA 24060 USA
| | - James R. Brown
- School of Molecular Sciences and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing Arizona State University Tempe AZ 85281 USA
| | - Clay B. Arrington
- Macromolecules Innovation Institute Department of Chemistry Virginia Tech Blacksburg VA 24060 USA
| | - Viswanath Meenakshisundaram
- Macromolecules Innovation Institute Department of Mechanical Engineering Virginia Tech Blacksburg VA 24061 USA
| | - Christopher B. Williams
- Macromolecules Innovation Institute Department of Mechanical Engineering Virginia Tech Blacksburg VA 24061 USA
| | - Timothy E. Long
- School of Molecular Sciences and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing Arizona State University Tempe AZ 85281 USA
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Gotsch SG, Williams CB, Bicaba R, Cruz-de Hoyos R, Darby A, Davidson K, Dix M, Duarte V, Glunk A, Green L, Ferguson B, Muñoz-Elizondo K, Murray JG, Picado-Fallas I, Nӕsborg R, Dawson TE, Nadkarni N. Trade-offs between succulent and non-succulent epiphytes underlie variation in drought tolerance and avoidance. Oecologia 2022; 198:645-661. [PMID: 35279723 DOI: 10.21203/rs.3.rs-899788/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 02/19/2022] [Indexed: 05/25/2023]
Abstract
Epiphyte communities comprise important components of many forest ecosystems in terms of biomass and diversity, but little is known regarding trade-offs that underlie diversity and structure in these communities or the impact that microclimate has on epiphyte trait allocation. We measured 22 functional traits in vascular epiphyte communities across six sites that span a microclimatic gradient in a tropical montane cloud forest region in Costa Rica. We quantified traits that relate to carbon and nitrogen allocation, gas exchange, water storage, and drought tolerance. Functional diversity was high in all but the lowest elevation site where drought likely limits the success of certain species with particular trait combinations. For most traits, variation was explained by relationships with other traits, rather than differences in microclimate across sites. Although there were significant differences in microclimate, epiphyte abundance, and diversity, we found substantial overlap in multivariate trait space across five of the sites. We found significant correlations between functional traits, many of which related to water storage (leaf water content, leaf thickness, hydrenchymal thickness), drought tolerance (turgor loss point), and carbon allocation (specific leaf area, leaf dry matter content). This suite of trait correlations suggests that the epiphyte community has evolved functional strategies along with a drought avoidance versus drought tolerance continuum where leaf succulence emerged as a pivotal overall trait.
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Affiliation(s)
- S G Gotsch
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA.
| | - C B Williams
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
- Conservation and Research, Santa Barbara Botanic Garden, Santa Barbara, CA, USA
- Channel Islands National Park, Ventura, CA, USA
| | - R Bicaba
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - R Cruz-de Hoyos
- Department of Integrative Biology, University of California-Berkeley, Berkeley, CA, USA
| | - A Darby
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - K Davidson
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY, USA
| | - M Dix
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, USA
| | - V Duarte
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - A Glunk
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - L Green
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - B Ferguson
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - K Muñoz-Elizondo
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - J G Murray
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
- Department of Biology, Utah State University, Logan, UT, USA
| | - I Picado-Fallas
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
| | - R Nӕsborg
- Department of Biology, Franklin and Marshall College, Lancaster, PA, USA
- Conservation and Research, Santa Barbara Botanic Garden, Santa Barbara, CA, USA
| | - T E Dawson
- Department of Integrative Biology, University of California-Berkeley, Berkeley, CA, USA
| | - N Nadkarni
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
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Bezek LB, Chatham CA, Dillard DA, Williams CB. Mechanical properties of tissue-mimicking composites formed by material jetting additive manufacturing. J Mech Behav Biomed Mater 2021; 125:104938. [PMID: 34740012 DOI: 10.1016/j.jmbbm.2021.104938] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/19/2021] [Accepted: 10/25/2021] [Indexed: 10/20/2022]
Abstract
Capitalizing on features including high resolution, smooth surface finish, large build volume, and simultaneous multi-color/multi-material printing, material jetting additive manufacturing enables the fabrication of full-scale anatomic models. The ability to print materials that resemble relevant, compliant tissues has especially motivated implementation of material jetting for patient-specific surgical planning or training models. In an effort to broaden the material selection for the material jetting process, and to provide materials that more closely mimic the functional needs for a wider variety of tissues, a composite material system is explored that uses non-curing fluid dispersed into a photo-curable medium. The material properties of the composites are examined through both thermal and mechanical analysis (dynamic mechanical analysis, Shore hardness testing, puncture testing, and tensile testing). Higher contributions of non-curing fluid generally reduce part strength and stiffness, and exponential and second-order polynomial expressions are appropriate fits for many of the mechanical properties as functions of non-curing fluid concentration. Through the fundamental exploration of the impact of an added diluent on material properties, the study advances knowledge on the process-property relationship for multi-material jetting. Additionally, better understanding of the mechanical property space offered by these materials will expand the capabilities of material jetting in the context of biomedical applications. The collection of mechanical properties serve as reference data sets to facilitate quicker screening for tissue-mimicking, medical models.
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Affiliation(s)
- Lindsey B Bezek
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Camden A Chatham
- Macromolecular Science & Engineering, Virginia Tech, Blacksburg, VA, 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - David A Dillard
- Macromolecular Science & Engineering, Virginia Tech, Blacksburg, VA, 24061, USA; Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Christopher B Williams
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA; Macromolecular Science & Engineering, Virginia Tech, Blacksburg, VA, 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA, 24061, USA.
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Arrington CB, Hegde M, Meenakshisundaram V, Dennis JM, Williams CB, Long TE. Supramolecular Salts for Additive Manufacturing of Polyimides. ACS Appl Mater Interfaces 2021; 13:48061-48070. [PMID: 34587443 DOI: 10.1021/acsami.1c13493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent advances in vat photopolymerization (VP) additive manufacturing of fully aromatic polyimides employed photoreactive high-molecular-weight precursors dissolved at modest loadings (<20 wt %) in organic solvent. These earlier efforts revealed high isotropic shrinkage, approaching 52% on a linear basis while converting to the desired polyimide. To increase the polyimide precursor concentration and decrease shrinkage during VP processing of high-performance polyimides, photoreactive fully aromatic polyimide and thermoplastic polyetherimide (PEI) supramolecular salt precursors now serve as versatile alternatives. Both pyromellitic dianhydride-4,4'-oxydianiline (PMDA-ODA) and 4,4'-(4,4'-isopropylidene-diphenoxy)diphthalic anhydride-meta phenylene diamine (BPADA-mPD) supramolecular dicarboxylate-diammonium salts, termed polysalts, provided prerequisite rheological performance and photoreactivity for VP. Solutions (50 wt %) of both photoactive polysalts exhibited viscosities more than two orders of magnitude lower than previously reported polyimide precursor solutions for VP. In addition, VP of 50 wt % polysalt solutions yielded high resolution, self-supporting organogel structures. During thermal postprocessing to the desired fully aromatic polyimide and PEI, photocrosslinked polysalt organogels exhibited retention of part shape in concert with linear isotropic shrinkage of only 26%, the lowest reported value using organogel strategies for VP of fully aromatic polyimides. Furthermore, the imidized structures exhibited comparable thermal and mechanical properties to analogous polyimides synthesized using classical methodologies for 2D films. The combination of facile synthesis and increased precursor concentrations designates polysalt polyimide precursors as a versatile platform for additive manufacturing of well-defined 3D polyimide structures.
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Affiliation(s)
- Clay B Arrington
- Biodesign Center for Sustainable Macromolecular Materials and Manufacturing & School of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
- Department of Chemistry, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Maruti Hegde
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Viswanath Meenakshisundaram
- Department of Mechanical Engineering and Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Joseph M Dennis
- United States Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
| | - Christopher B Williams
- Department of Mechanical Engineering and Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Timothy E Long
- Biodesign Center for Sustainable Macromolecular Materials and Manufacturing & School of Molecular Sciences, Arizona State University, Tempe, Arizona 85281, United States
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Hamachi LS, Rau DA, Arrington CB, Sheppard DT, Fortman DJ, Long TE, Williams CB, Dichtel WR. Dissociative Carbamate Exchange Anneals 3D Printed Acrylates. ACS Appl Mater Interfaces 2021; 13:38680-38687. [PMID: 34369767 DOI: 10.1021/acsami.1c09373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Relative to other additive manufacturing modalities, vat photopolymerization (VP) offers designers superior surface finish, feature resolution, and throughput. However, poor interlayer network formation can limit a VP-printed part's tensile strength along the build axis. We demonstrate that the incorporation of carbamate bonds capable of undergoing dissociative exchange reactions provides improved interlayer network formation in VP-printed urethane acrylate polymers. In the presence of dibutyltin dilaurate catalyst, the exchange of these carbamate bonds enables rapid stress relaxation with an activation energy of 133 kJ/mol, consistent with a dissociative bond exchange process. Annealed XY tensile samples containing a catalyst demonstrate a 25% decrease in Young's modulus, attributed to statistical changes in network topology, while samples without a catalyst show no observable effect. Annealed ZX tensile samples printed with layers perpendicular to tensile load demonstrate an increase in elongation at break, indicative of self-healing. The strain at break for samples containing a catalyst increases from 33.9 to 56.0% after annealing but decreases from 48.1 to 32.1% after annealing in samples without a catalyst. This thermally activated bond exchange process improves the performance of VP-printed materials via self-healing across layers and provides a means to change Young's modulus after printing. Thus, the incorporation of carbamate bonds and appropriate catalysts in the VP-printing process provides a robust platform for enhancing material properties and performance.
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Affiliation(s)
- Leslie S Hamachi
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Daniel A Rau
- Department of Mechanical Engineering, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Clay B Arrington
- Department of Chemistry, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Daylan T Sheppard
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - David J Fortman
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14853, United States
| | - Timothy E Long
- School of Molecular Sciences, Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Arizona State University, Tempe, Arizona 85281, United States
| | - Christopher B Williams
- Department of Mechanical Engineering, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - William R Dichtel
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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Bezek LB, Pan J, Harb C, Zawaski CE, Molla B, Kubalak JR, Marr LC, Williams CB. Additively manufactured respirators: quantifying particle transmission and identifying system-level challenges for improving filtration efficiency. J Manuf Syst 2021; 60:762-773. [PMID: 33551537 PMCID: PMC7846466 DOI: 10.1016/j.jmsy.2021.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 05/09/2023]
Abstract
The COVID-19 pandemic has disrupted the supply chain for personal protective equipment (PPE) for medical professionals, including N95-type respiratory protective masks. To address this shortage, many have looked to the agility and accessibility of additive manufacturing (AM) systems to provide a democratized, decentralized solution to producing respirators with equivalent protection for last-resort measures. However, there are concerns about the viability and safety in deploying this localized download, print, and wear strategy due to a lack of commensurate quality assurance processes. Many open-source respirator designs for AM indicate that they do not provide N95-equivalent protection (filtering 95% of SARS-CoV-2 particles) because they have either not passed aerosol generation tests or not been tested. Few studies have quantified particle transmission through respirator designs outside of the filter medium. This is concerning because several polymer-based AM processes produce porous parts, and inherent process variation between printers and materials also threaten the integrity of tolerances and seals within the printed respirator assembly. No study has isolated these failure mechanisms specifically for respirators. The goal of this paper is to measure particle transmission through printed respirators of different designs, materials, and AM processes. The authors compare the performance of printed respirators to N95 respirators and cloth masks. Respirators in this study printed using desktop- and industrial-scale fused filament fabrication processes and industrial-scale powder bed fusion processes were not sufficiently reliable for widespread distribution and local production of N95-type respiratory protection. Even while assuming a perfect seal between the respirator and the user's face, although a few respirators provided >90% efficiency at the 100-300 nm particle range, almost all printed respirators provided <60% filtration efficiency. Post-processing procedures including cleaning, sealing surfaces, and reinforcing the filter cap seal generally improved performance, but the printed respirators showed similar performance to various cloth masks. The authors further explore the process-driven aspects leading to low filtration efficiency. Although the design/printer/material combination dictates the AM respirator performance, the identified failure modes originate from system-level constraints and are therefore generalizable across multiple AM processes. Quantifying the limitations of AM in producing N95-type respiratory protective masks advances understanding of AM systems toward the development of better part and machine designs to meet the needs of reliable, functional, end-use parts.
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Affiliation(s)
- Lindsey B Bezek
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Jin Pan
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Charbel Harb
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Callie E Zawaski
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Bemnet Molla
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Joseph R Kubalak
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Christopher B Williams
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, United States
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White BT, Meenakshisundaram V, Feller KD, Williams CB, Long TE. Vat photopolymerization of unsaturated polyesters utilizing a polymerizable ionic liquid as a non-volatile reactive diluent. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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10
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Abstract
Fully aromatic polyimides are amenable to efficient carbonization in thin two-dimensional (2D) films due to a complement of aromaticity and planarity of backbone repeating units. However, repeating unit rigidity traditionally imposes processing limitations, restricting many fully aromatic polyimides, e.g., pyromellitic dianhydride with 4,4'-oxidianiline (PMDA-ODA) polyimides, to a 2D form factor. Recently, research efforts in our laboratories enabled additive manufacturing of micron-scale resolution PMDA-ODA polyimide objects using vat photopolymerization (VP) and ultraviolet-assisted direct ink write (UV-DIW) following careful thermal postprocessing of the three-dimensional (3D) organogel precursors to 400 °C. Further thermal postprocessing of printed objects to 1000 °C induced pyrolysis of the PMDA-ODA objects to disordered carbon. The pyrolyzed objects retained excellent geometric resolution, and Raman spectroscopy displayed characteristic disordered (D) and graphitic (G) carbon bands. Scanning electron microscopy probed the cross-sectional homogeneity of the carbonized samples, revealing an absence of pore formation during carbonization. Likewise, impedance analysis of carbonized specimens indicated only a moderate decrease in conductivity compared to thin films that were pyrolyzed using an identical carbonization process. Facile pyrolysis of PMDA-ODA objects now enables the production of carbonaceous monoliths with complex and predictable three-dimensional geometries using commercially available starting materials.
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Affiliation(s)
- Clay B. Arrington
- Virginia Tech, Department of Chemistry and Macromolecules Innovation Institute (MII), Blacksburg, Virginia 24061, United States
| | - Daniel A. Rau
- Virginia Tech, Department of Mechanical Engineering and Macromolecules Innovation Institute (MII), Blacksburg, Virginia 24061, United States
| | - Johanna A. Vandenbrande
- Arizona State University, School of Molecular Science and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Tempe, Arizona 85281, United States
| | - Maruti Hegde
- University of North Carolina at Chapel Hill, Applied Physical Sciences, Chapel Hill, North Carolina 27599, United States
| | - Christopher B. Williams
- Virginia Tech, Department of Mechanical Engineering and Macromolecules Innovation Institute (MII), Blacksburg, Virginia 24061, United States
| | - Timothy E. Long
- Arizona State University, School of Molecular Science and Biodesign Center for Sustainable Macromolecular Materials and Manufacturing, Tempe, Arizona 85281, United States
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Arrington CB, Rau DA, Williams CB, Long TE. UV-assisted direct ink write printing of fully aromatic Poly(amide imide)s: Elucidating the influence of an acrylic scaffold. POLYMER 2021. [DOI: 10.1016/j.polymer.2020.123306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chen X, Zawaski CE, Spiering GA, Liu B, Orsino CM, Moore RB, Williams CB, Long TE. Quadruple Hydrogen Bonding Supramolecular Elastomers for Melt Extrusion Additive Manufacturing. ACS Appl Mater Interfaces 2020; 12:32006-32016. [PMID: 32520520 DOI: 10.1021/acsami.0c08958] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This manuscript describes the versatility of highly directional, noncovalent interactions, i.e., quadruple hydrogen bonding (QHB), to afford novel polyurea segmented supramolecular polymers for melt extrusion three-dimensional (3D) printing processes. The molecular design of the polyurea elastomers features (1) flexible polyether segments and relatively weak urea hydrogen-bonding sites in the soft segments to provide elasticity and toughness, and (2) strong ureido-cytosine (UCyt) QHB in the hard segments to impart enhanced mechanical integrity. The resulting polyureas were readily compression-molded into mechanically-robust, transparent, and creasable films. Optimization of polyurea composition offered a rare combination of high tensile strength (95 MPa), tensile elongation (788% strain), and toughness (94 MJ/m3), which are superior to a commercially available Ninjaflex elastomer. The incorporation of QHB facilitated melt processability, where hydrogen bonding dissociation provided low viscosities at printing temperatures. During cooling, directional self-assembly of UCyt QHB facilitated the solidification process and contributed to part fidelity with the formation of a robust physical network. The printed objects displayed high layer fidelity, smooth surfaces, minimal warpage, and complex geometries. The presence of highly directional QHB effectively diminished mechanical anisotropy, and the printed samples exhibited comparable Young's moduli along (x-y direction, 0°) and perpendicular to (z-direction, 90°) the layer direction. Remarkably, the printed samples exhibited ultimate tensile strains approaching 500% in the z-direction prior to failure, which was indicative of improved interlayer adhesion. Thus, this design paradigm, which is demonstrated for novel polyurea copolymers, suggests the potential of supramolecular polymers with enhanced mechanical performance, melt processability, recyclability, and improved interlayer adhesion for melt extrusion additive manufacturing processes.
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Affiliation(s)
- Xi Chen
- Department of Chemistry, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Callie E Zawaski
- Department of Mechanical Engineering, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Glenn A Spiering
- Department of Chemistry, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Boer Liu
- Department of Chemistry, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Christina M Orsino
- Department of Chemistry, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Robert B Moore
- Department of Chemistry, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Christopher B Williams
- Department of Mechanical Engineering, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Timothy E Long
- Department of Chemistry, Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
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Bezek LB, Cauchi MP, De Vita R, Foerst JR, Williams CB. 3D printing tissue-mimicking materials for realistic transseptal puncture models. J Mech Behav Biomed Mater 2020; 110:103971. [PMID: 32763836 DOI: 10.1016/j.jmbbm.2020.103971] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/23/2020] [Accepted: 06/29/2020] [Indexed: 01/09/2023]
Abstract
Applications of additive manufacturing (commonly referred to as 3D printing) in direct fabrication of models for pre-surgical planning, functional testing, and medical training are on the rise. However, one current limitation to the accuracy of models for cardiovascular procedural training is a lack of printable materials that accurately mimic human tissue. Most of the available elastomeric materials lack mechanical properties representative of human tissues. To address the gap, the authors explore the multi-material capability of material jetting additive manufacturing to combine non-curing and photo-curing inks to achieve material properties that more closely replicate human tissues. The authors explore the impact of relative material concentration on tissue-relevant properties from puncture and tensile testing under submerged conditions. Further, the authors demonstrate the ability to mimic the mechanical properties of the fossa ovalis, which proves beneficial for accurately simulating transseptal punctures. A fossa ovalis mimic was printed and assembled within a full patient-specific heart model for validation, where it exhibited accuracy in both mechanical properties and geometry. The explored material combination provides the opportunity to fabricate future medical models that are more realistic and better suited for pre-surgical planning and medical student training. This will ultimately guide safer, more efficient practices.
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Affiliation(s)
- Lindsey B Bezek
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | | | - Raffaella De Vita
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Jason R Foerst
- Section of Interventional and Structural Cardiology, Virginia Tech Carilion School of Medicine, Roanoke, VA, 24016, USA
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Wilts EM, Gula A, Davis C, Chartrain N, Williams CB, Long TE. Corrigendum to “Vat photopolymerization of liquid, biodegradable PLGA-based oligomers as tissue scaffolds” [Eur. Polym. J. 130 (2020) 109693]. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2020.109735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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15
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Wilts EM, Gula A, Davis C, Chartrain N, Williams CB, Long TE. Vat photopolymerization of liquid, biodegradable PLGA-based oligomers as tissue scaffolds. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2020.109693] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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16
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Scott PJ, Meenakshisundaram V, Hegde M, Kasprzak CR, Winkler CR, Feller KD, Williams CB, Long TE. 3D Printing Latex: A Route to Complex Geometries of High Molecular Weight Polymers. ACS Appl Mater Interfaces 2020; 12:10918-10928. [PMID: 32028758 DOI: 10.1021/acsami.9b19986] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Vat photopolymerization (VP) additive manufacturing fabricates intricate geometries with excellent resolution; however, high molecular weight polymers are not amenable to VP due to concomitant high solution and melt viscosities. Thus, a challenging paradox arises between printability and mechanical performance. This report describes concurrent photopolymer and VP system design to navigate this paradox with the unprecedented use of polymeric colloids (latexes) that effectively decouple the dependency of viscosity on molecular weight. Photocrosslinking of a continuous-phase scaffold, which surrounds the latex particles, combined with in situ computer-vision print parameter optimization, which compensates for light scattering, enables high-resolution VP of high molecular weight polymer latexes as particle-embedded green bodies. Thermal post-processing promotes coalescence of the dispersed particles throughout the scaffold, forming a semi-interpenetrating polymer network without loss in part resolution. Printing a styrene-butadiene rubber latex, a previously inaccessible elastomer composition for VP, exemplified this approach and yielded printed elastomers with precise geometry and tensile extensibilities exceeding 500%.
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Affiliation(s)
- Philip J Scott
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Viswanath Meenakshisundaram
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Maruti Hegde
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, North Carolina 27514, United States
| | - Christopher R Kasprzak
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Christopher R Winkler
- Nanoscale Characterization and Fabrication Laboratory (NCFL), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Keyton D Feller
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Christopher B Williams
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Timothy E Long
- Macromolecules Innovation Institute, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
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Scott PJ, Kasprzak CR, Feller KD, Meenakshisundaram V, Williams CB, Long TE. Light and latex: advances in the photochemistry of polymer colloids. Polym Chem 2020. [DOI: 10.1039/d0py00349b] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Unparalleled temporal and spatial control of colloidal chemical processes introduces immense potential for the manufacturing, modification, and manipulation of latex particles.
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Affiliation(s)
- Philip J. Scott
- Department of Chemistry
- Macromolecules Innovation Institute
- Virginia Tech
- Blacksburg
- USA
| | | | - Keyton D. Feller
- Department of Mechanical Engineering
- Macromolecules Innovation Institute
- Virginia Tech
- Blacksburg
- USA
| | | | - Christopher B. Williams
- Department of Mechanical Engineering
- Macromolecules Innovation Institute
- Virginia Tech
- Blacksburg
- USA
| | - Timothy E. Long
- Department of Chemistry
- Macromolecules Innovation Institute
- Virginia Tech
- Blacksburg
- USA
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Herzberger J, Sirrine JM, Williams CB, Long TE. Polymer Design for 3D Printing Elastomers: Recent Advances in Structure, Properties, and Printing. Prog Polym Sci 2019. [DOI: 10.1016/j.progpolymsci.2019.101144] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Zawaski CE, Wilts EM, Chatham CA, Stevenson AT, Pekkanen AM, Li C, Tian Z, Whittington AR, Long TE, Williams CB. Tuning the material properties of a water-soluble ionic polymer using different counterions for material extrusion additive manufacturing. POLYMER 2019. [DOI: 10.1016/j.polymer.2019.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Appuhamillage GA, Chartrain N, Meenakshisundaram V, Feller KD, Williams CB, Long TE. 110th Anniversary: Vat Photopolymerization-Based Additive Manufacturing: Current Trends and Future Directions in Materials Design. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b02679] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Wilts EM, Ma D, Bai Y, Williams CB, Long TE. Comparison of Linear and 4-Arm Star Poly(vinyl pyrrolidone) for Aqueous Binder Jetting Additive Manufacturing of Personalized Dosage Tablets. ACS Appl Mater Interfaces 2019; 11:23938-23947. [PMID: 31252452 DOI: 10.1021/acsami.9b08116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Fabrication of personalized dosage oral pharmaceuticals using additive manufacturing (AM) provides patients with customizable, locally manufactured, and cost-efficient tablets, while reducing the probability of side effects. Binder jetting AM has potential for fabrication of customized dosage tablets, but the resulting products lack in strength due to solely relying on the binder to produce structural integrity. The selection of polymeric binders is also limited due to viscosity restraints, which limits molecular weight and concentration. To investigate and ameliorate these limitations, this article reports a comprehensive study of linear and 4-arm star poly(vinyl pyrrolidone) (PVP) over a range of molecular weights as polymeric binders for binder jetting AM and their effect on physical tablet properties. Formulation of varying molecular weights and concentrations of linear and 4-arm star PVP in deionized water and subsequent jetting revealed relationships between the critical overlap concentrations (C*) and jettability on binder jetting systems with thermal inkjet printheads. After printing with a commercially available ZCorp Spectrum Z510 printer with an HP11 printhead with a lactose and powdered sugar powder bed, subsequent measurement of compressive strength, compressive modulus, and porosity revealed structure-property relationships between molecular weight, polymer concentration, and linear and 4-arm star architectures with physical properties of binder jetted tablets. This study elucidated that the dominating factor to increase compressive strength of a tablet is dependent on the weight percent of the polymer in the binder, which filled interstitial voids between powder particles. Because 4-arm star polymers have lower solution viscosities compared to linear analogues at the same molecular weights, they were jettable at higher concentrations, thus producing the strongest tablets at a compressive strength of 1.2 MPa. Finally, the inclusion of an active pharmaceutical ingredient (API), acetaminophen, revealed maintenance of the tablet physical properties across 5-50 total wt % API in each tablet.
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Chatham CA, Long TE, Williams CB. A review of the process physics and material screening methods for polymer powder bed fusion additive manufacturing. Prog Polym Sci 2019. [DOI: 10.1016/j.progpolymsci.2019.03.003] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Sirrine JM, Zlatanic A, Meenakshisundaram V, Messman JM, Williams CB, Dvornic PR, Long TE. 3D Printing Amorphous Polysiloxane Terpolymers via Vat Photopolymerization. MACROMOL CHEM PHYS 2019. [DOI: 10.1002/macp.201800425] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Justin M. Sirrine
- Department of Chemistry Macromolecules Innovation Institute Virginia Tech Blacksburg VA 24061 USA
| | - Alisa Zlatanic
- Kansas Polymer Research Center Pittsburg State University Pittsburg KS 66762 USA
| | - Viswanath Meenakshisundaram
- Department of Mechanical Engineering Macromolecules Innovation Institute Virginia Tech Blacksburg VA 24061 USA
| | - Jamie M. Messman
- Honeywell Federal Manufacturing & Technologies LLC Kansas City MO 64147 USA
| | - Christopher B. Williams
- Department of Mechanical Engineering Macromolecules Innovation Institute Virginia Tech Blacksburg VA 24061 USA
| | - Petar R. Dvornic
- Department of Chemistry Pittsburg State University Pittsburg KS 66762 USA
| | - Timothy E. Long
- Department of Chemistry Macromolecules Innovation Institute Virginia Tech Blacksburg VA 24061 USA
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Wilts EM, Pekkanen AM, White BT, Meenakshisundaram V, Aduba DC, Williams CB, Long TE. Vat photopolymerization of charged monomers: 3D printing with supramolecular interactions. Polym Chem 2019. [DOI: 10.1039/c8py01792a] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vat photopolymerization of a trimethylammonium ethyl acrylate chloride solution (TMAEA) resulted in a well-defined, fully soluble, 3D printed rook.
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Affiliation(s)
- Emily M. Wilts
- Department of Chemistry
- Macromolecules Innovation Institute
- Blacksburg
- USA
| | | | - B. Tyler White
- Department of Chemistry
- Macromolecules Innovation Institute
- Blacksburg
- USA
| | | | | | | | - Timothy E. Long
- Department of Chemistry
- Macromolecules Innovation Institute
- Blacksburg
- USA
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Affiliation(s)
- Timothy E Long
- Department of Chemistry, Virginia Tech, Blacksburg, VA 24061, USA.
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Rau DA, Herzberger J, Long TE, Williams CB. Ultraviolet-Assisted Direct Ink Write to Additively Manufacture All-Aromatic Polyimides. ACS Appl Mater Interfaces 2018; 10:34828-34833. [PMID: 30289680 DOI: 10.1021/acsami.8b14584] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
All-aromatic polyimides have degradation temperatures above 500 °C, excellent mechanical strength, and chemical resistance, and are thus ideal polymers for high-temperature applications. However, their all-aromatic structure impedes additive manufacturing (AM) because of the lack of melt processability and insolubility in organic solvents. Recently, our group demonstrated the design of UV-curable polyamic acids (PAA), the precursor of polyimides, to enable their processing using vat photopolymerization AM. This work leverages our previous synthetic strategy and combines it with the high solution viscosity of nonisolated PAA to yield suitable UV-curable inks for UV-assisted direct ink write (UV-DIW). UV-DIW enabled the design of complex three-dimensional structures comprising of thin features, such as truss structures. Dynamic mechanical analysis of printed and imidized specimens confirmed the thermomechanical properties typical of all-aromatic polyimides, showing a storage modulus above 1 GPa up to 400 °C. Processing polyimide precursors via DIW presents opportunity for multimaterial printing of multifunctional components, such as three-dimensional integrated electronics.
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Bai Y, Williams CB. The effect of inkjetted nanoparticles on metal part properties in binder jetting additive manufacturing. Nanotechnology 2018; 29:395706. [PMID: 29968575 DOI: 10.1088/1361-6528/aad0bb] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Binder jetting AM has been used to fabricate metal parts by first jetting a binder into a powder bed, and then sintering the resulting green part wherein the binder is removed and the metal particles are fused. Sintered part properties can be enhanced when nanoparticles are suspended into a solvent-based organic binder, as the inkjetted nanoparticles can reduce sintering shrinkage and increase mechanical strength. In this work, the authors also used a nanoparticle suspension without organic adhesives as a means for binding metal powder bed particles together. After being deposited into the powder particles' interstices, the jetted nanoparticles are sintered at a temperature lower than the powder sintering temperature via a heated powder bed, to provide strength to the printed green part. Compared to organic binders, the use of jetted nanoparticles provided a permanent bonding which improved the structural integrity of printed parts during sintering.
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Sirrine JM, Meenakshisundaram V, Moon NG, Scott PJ, Mondschein RJ, Weiseman TF, Williams CB, Long TE. Functional siloxanes with photo-activated, simultaneous chain extension and crosslinking for lithography-based 3D printing. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.02.056] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Gilmer EL, Miller D, Chatham CA, Zawaski C, Fallon JJ, Pekkanen A, Long TE, Williams CB, Bortner MJ. Model analysis of feedstock behavior in fused filament fabrication: Enabling rapid materials screening. POLYMER 2018. [DOI: 10.1016/j.polymer.2017.11.068] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Chartrain NA, Williams CB, Whittington AR. A review on fabricating tissue scaffolds using vat photopolymerization. Acta Biomater 2018; 74:90-111. [PMID: 29753139 DOI: 10.1016/j.actbio.2018.05.010] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 04/23/2018] [Accepted: 05/08/2018] [Indexed: 12/11/2022]
Abstract
Vat Photopolymerization (stereolithography, SLA), an Additive Manufacturing (AM) or 3D printing technology, holds particular promise for the fabrication of tissue scaffolds for use in regenerative medicine. Unlike traditional tissue scaffold fabrication techniques, SLA is capable of fabricating designed scaffolds through the selective photopolymerization of a photopolymer resin on the micron scale. SLA offers unprecedented control over scaffold porosity and permeability, as well as pore size, shape, and interconnectivity. Perhaps even more significantly, SLA can be used to fabricate vascular networks that may encourage angio and vasculogenesis. Fulfilling this potential requires the development of new photopolymers, the incorporation of biochemical factors into printed scaffolds, and an understanding of the effects scaffold geometry have on cell viability, proliferation, and differentiation. This review compares SLA to other scaffold fabrication techniques, highlights significant advances in the field, and offers a perspective on the field's challenges and future directions. STATEMENT OF SIGNIFICANCE Engineering de novo tissues continues to be challenging due, in part, to our inability to fabricate complex tissue scaffolds that can support cell proliferation and encourage the formation of developed tissue. The goal of this review is to first introduce the reader to traditional and Additive Manufacturing scaffold fabrication techniques. The bulk of this review will then focus on apprising the reader of current research and provide a perspective on the promising use of vat photopolymerization (stereolithography, SLA) for the fabrication of complex tissue scaffolds.
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Affiliation(s)
- Nicholas A Chartrain
- Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24061, USA; Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Christopher B Williams
- Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24061, USA; Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Abby R Whittington
- Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24061, USA; Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA; Department of Chemical Engineering, Virginia Tech, Blacksburg, VA 24061, USA.
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Herzberger J, Meenakshisundaram V, Williams CB, Long TE. 3D Printing All-Aromatic Polyimides Using Stereolithographic 3D Printing of Polyamic Acid Salts. ACS Macro Lett 2018; 7:493-497. [PMID: 35619348 DOI: 10.1021/acsmacrolett.8b00126] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polyamic acid (PAA) salts are amenable to photocuring additive manufacturing processes of all-aromatic polyimides. Due to an all-aromatic structure, these high-performance polymers are exceptionally chemically and thermally stable but are not conventionally processable in their imidized form. The facile addition of 2-(dimethylamino)ethyl methacrylate (DMAEMA) to commercially available poly(4,4'-oxydiphenylene pyromellitamic acid) (PMDA-ODA PAA) afforded ultraviolet curable PAA salt solutions. These readily prepared solutions do not require multistep synthesis, exhibited fast gel times (<5 s), and rendered high G' gel-state moduli. Vat photopolymerization 3D printing afforded self-supporting organogels. Subsequent thermal treatment rendered the cross-linked PAA precursor to all-aromatic PMDA-ODA polyimide. This fast and facile strategy makes PMDA-ODA polyimides accessible in three dimensions and offers impact on aerospace or automotive technologies.
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Affiliation(s)
- Jana Herzberger
- Department of Chemistry and Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Viswanath Meenakshisundaram
- Department of Mechanical Engineering and Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Christopher B. Williams
- Department of Mechanical Engineering and Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Timothy E. Long
- Department of Chemistry and Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States
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Al-Abdwani R, Williams CB, Dunn C, Macartney J, Wollny K, Frndova H, Chin N, Stephens D, Parshuram CS. Incidence, outcomes and outcome prediction of unplanned extubation in critically ill children: An 11year experience. J Crit Care 2017; 44:368-375. [PMID: 29289914 DOI: 10.1016/j.jcrc.2017.12.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 11/06/2017] [Accepted: 12/22/2017] [Indexed: 12/27/2022]
Abstract
PURPOSE Unplanned extubation represents loss of control in the ICU, is associated with harm and is used as a measure of quality of care. We evaluated the rates and consequences of unplanned extubation. MATERIALS AND METHODS Eligible patients were intubated, <18years, and in ICU. Patient, care-related and environmental characteristics were compared in patients who did and did not receive positive pressure ventilation in the 24h after events. Rates are expressed per 100 intubation-days. RESULTS The 11,310 eligible patient-admissions identified were intubated for 75,519days; 410 (3.39%) patients had 458 unplanned extubation events (0.61 events/100 intubation-days). Annual rates of unplanned extubation reduced from 0.98 in 2004 to 0.37 in 2014. Consequences occurred in 245 (53.5%) events and included cardiac arrest in 9 (2%), bradycardia 52 (11%), and stridor 63 (14%). Positive pressure was provided after 263 (57%) events, and was independently associated with pre-event sedative and muscle relaxant drugs, non-use of restraints, respiratory reason for intubation and recent care by more nurses. CONCLUSION Unplanned extubation was associated with both significant and no morbidity. Modification of factors including more consistent nurse staffing, restraint use, and increased vigilance in patients with previous events may potentially reduce rates and adverse consequences of unplanned extubation.
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Affiliation(s)
- R Al-Abdwani
- Centre for Safety Research, Department of Critical Care Medicine, Hospital for Sick Children, Canada
| | - C B Williams
- Centre for Safety Research, Department of Critical Care Medicine, Hospital for Sick Children, Canada
| | - C Dunn
- Critical Care Program, Hospital for Sick Children, Canada
| | - J Macartney
- Critical Care Program, Hospital for Sick Children, Canada
| | - K Wollny
- Critical Care Program, Hospital for Sick Children, Canada
| | - H Frndova
- Centre for Safety Research, Critical Care Program, Hospital for Sick Children, Canada
| | - N Chin
- Critical Care Program, Informatics, Hospital for Sick Children, Canada
| | - D Stephens
- Child Health and Evaluation Sciences Program, The Research Institute, Hospital for Sick Children, Canada
| | - C S Parshuram
- Department of Critical Care Medicine, Department of Paediatrics, Child Health and Evaluation Sciences Program, The Research Institute, Centre for Safety Research Hospital for Sick Children, Canada; Department of Pediatrics, Interdepartmental Division of Critical Care Medicine, Department of Health Policy Management and Evaluation, University of Toronto, Canada.
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Pekkanen AM, Mondschein RJ, Williams CB, Long TE. 3D Printing Polymers with Supramolecular Functionality for Biological Applications. Biomacromolecules 2017; 18:2669-2687. [PMID: 28762718 DOI: 10.1021/acs.biomac.7b00671] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Supramolecular chemistry continues to experience widespread growth, as fine-tuned chemical structures lead to well-defined bulk materials. Previous literature described the roles of hydrogen bonding, ionic aggregation, guest/host interactions, and π-π stacking to tune mechanical, viscoelastic, and processing performance. The versatility of reversible interactions enables the more facile manufacturing of molded parts with tailored hierarchical structures such as tissue engineered scaffolds for biological applications. Recently, supramolecular polymers and additive manufacturing processes merged to provide parts with control of the molecular, macromolecular, and feature length scales. Additive manufacturing, or 3D printing, generates customizable constructs desirable for many applications, and the introduction of supramolecular interactions will potentially increase production speed, offer a tunable surface structure for controlling cell/scaffold interactions, and impart desired mechanical properties through reinforcing interlayer adhesion and introducing gradients or self-assembled structures. This review details the synthesis and characterization of supramolecular polymers suitable for additive manufacture and biomedical applications as well as the use of supramolecular polymers in additive manufacturing for drug delivery and complex tissue scaffold formation. The effect of supramolecular assembly and its dynamic behavior offers potential for controlling the anisotropy of the printed objects with exquisite geometrical control. The potential for supramolecular polymers to generate well-defined parts, hierarchical structures, and scaffolds with gradient properties/tuned surfaces provides an avenue for developing next-generation biomedical devices and tissue scaffolds.
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Affiliation(s)
- Allison M Pekkanen
- School of Biomedical Engineering and Sciences, Virginia Tech , Blacksburg, Virginia 24061, United States.,Macromolecules Innovation Institute (MII), Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Ryan J Mondschein
- Macromolecules Innovation Institute (MII), Virginia Tech , Blacksburg, Virginia 24061, United States.,Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Christopher B Williams
- Macromolecules Innovation Institute (MII), Virginia Tech , Blacksburg, Virginia 24061, United States.,Department of Mechanical Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Timothy E Long
- Macromolecules Innovation Institute (MII), Virginia Tech , Blacksburg, Virginia 24061, United States.,Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States
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Pekkanen AM, Zawaski C, Stevenson AT, Dickerman R, Whittington AR, Williams CB, Long TE. Poly(ether ester) Ionomers as Water-Soluble Polymers for Material Extrusion Additive Manufacturing Processes. ACS Appl Mater Interfaces 2017; 9:12324-12331. [PMID: 28329442 DOI: 10.1021/acsami.7b01777] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Water-soluble polymers as sacrificial supports for additive manufacturing (AM) facilitate complex features in printed objects. Few water-soluble polymers beyond poly(vinyl alcohol) enable material extrusion AM. In this work, charged poly(ether ester)s with tailored rheological and mechanical properties serve as novel materials for extrusion-based AM at low temperatures. Melt transesterification of poly(ethylene glycol) (PEG, 8k) and dimethyl 5-sulfoisophthalate afforded poly(ether ester)s of sufficient molecular weight to impart mechanical integrity. Quantitative ion exchange provided a library of poly(ether ester)s with varying counterions, including both monovalent and divalent cations. Dynamic mechanical and tensile analysis revealed an insignificant difference in mechanical properties for these polymers below the melting temperature, suggesting an insignificant change in final part properties. Rheological analysis, however, revealed the advantageous effect of divalent countercations (Ca2+, Mg2+, and Zn2+) in the melt state and exhibited an increase in viscosity of two orders of magnitude. Furthermore, time-temperature superposition identified an elevation in modulus, melt viscosity, and flow activation energy, suggesting intramolecular interactions between polymer chains and a higher apparent molecular weight. In particular, extrusion of poly(PEG8k-co-CaSIP) revealed vast opportunities for extrusion AM of well-defined parts. The unique melt rheological properties highlighted these poly(ether ester) ionomers as ideal candidates for low-temperature material extrusion additive manufacturing of water-soluble parts.
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Affiliation(s)
- Allison M Pekkanen
- School of Biomedical Engineering and Sciences, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Callie Zawaski
- Department of Mechanical Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - André T Stevenson
- Department of Materials Science and Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Ross Dickerman
- Department of Chemical Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Abby R Whittington
- School of Biomedical Engineering and Sciences, Virginia Tech , Blacksburg, Virginia 24061, United States
- Department of Materials Science and Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
- Department of Chemical Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Christopher B Williams
- Department of Mechanical Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
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Hirshfield KM, Paratala BS, Hindoyan A, Dolfi SC, Yilmazel B, Schrock A, Gay L, Ali SM, Ross JS, Williams CB, Nair P, Ganesan S, Leyland-Jones B. Abstract P3-07-02: Are we missing actionable targets in breast cancer? Novel insights into recurrent Ret alterations. Cancer Res 2017. [DOI: 10.1158/1538-7445.sabcs16-p3-07-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: Recurrent gene fusions in breast cancer have been rarely reported suggesting that they either are not present or are not easily detected by standard sequencing methods. Comprehensive genomic profiling (CGP) by hybrid capture-based, high depth next-generation sequencing approaches, can be used to detect recurrent rearrangements and other genomic alterations involving target genes. We found that CGP can identify recurrent alterations involving RET, a known oncogenic tyrosine receptor kinase, in a subset of breast cancer.
Methods: CGP using FoundationOne platform was performed interrogating the entire coding region for up to 315 cancer-related genes and introns of up to 28 genes involved in rearrangements at a depth of 500-1000X in formalin-fixed, paraffin embedded tumor tissue (Foundation Medicine, MA). Engineered representative RET fusion vectors were synthesized and expressed in non-tumorigenic cell lines (breast MCF10A and mouse 3T3 fibroblasts), and cells were evaluated for RET kinase signaling, drug response, and tumorigenicity. Patient-derived xenografts (PDX) generated from two triple negative breast cancers (TNBCs) were used in an ex vivo assay (Response3DXTM, Molecular Response LLC, San Diego, CA).
Results: Twenty-two RET rearrangements were identified in 8119 (0.27%) breast cancer cases. Of these, 5 rearrangements were activating RET fusions including CCDC6-RET (n=4) and NCOA4-RET (n=1), that have been described in other cancer types. Five other cases had clear evidence of genomic rearrangement involving RET, but the 5' partners could not be definitively identified. The remaining twelve cases had complex rearrangements of RET including internal duplications. RET amplification was also observed, both in TNBC and in a HER2+ breast cancer at onset of resistance to HER2-targeted therapy.
Both NCOA4-RET and a novel RASGEF1A-RET fusion were characterized in vitro. Non-tumorigenic cells engineered to stably overexpress either RET fusions demonstrated transformed phenotypes. The fusions were constitutively active, as shown by endogenous phosphorylation of the kinase domain, and drove activation of downstream signaling as shown by increased phosphorylation of ERK and AKT. Cells transformed by RET-fusions were exquisitely sensitive to treatment with RET inhibitors. Interestingly, a PDX model of RET-amplified TNBC was sensitive to treatment with a PIK3CA inhibitor. An index case of ER+/PR-/HER2+, metastatic breast cancer that had radiographic evidence of disease progression while on trastuzumab, pertuzumab, and anastrazole was found to have a NCOA4-RET fusion by CGP. Subsequent treatment with with cabozantinib plus anastrazole led a rapid clinical and radiographic response.
Conclusions: CGP can identify recurrent RET rearrangements in breast cancer that act as primary oncogenic drivers and can be therapeutically targeted. RET alterations may also play a role in acquired resistance to HER2-targeted therapies, suggesting a role for combined RET and HER2-targeted therapy in this setting. Our data demonstrate that RET alterations can be identified by clinical-grade CGP and are promising candidates as therapeutic targets in selected breast cancer patients.
Citation Format: Hirshfield KM, Paratala BS, Hindoyan A, Dolfi SC, Yilmazel B, Schrock A, Gay L, Ali SM, Ross JS, Williams CB, Nair P, Ganesan S, Leyland-Jones B. Are we missing actionable targets in breast cancer? Novel insights into recurrent Ret alterations [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-07-02.
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Affiliation(s)
- KM Hirshfield
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - BS Paratala
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - A Hindoyan
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - SC Dolfi
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - B Yilmazel
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - A Schrock
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - L Gay
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - SM Ali
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - JS Ross
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - CB Williams
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - P Nair
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - S Ganesan
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
| | - B Leyland-Jones
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ; Molecular Response LLC, San Diego, CA; Foundation Medicine, Cambridge, MA; Avera Center for Precision Oncology, Sioux Falls, SD
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Williams CB, Krie A, De P, Dey N, Klein J, Williams KA, Hoogeveen M, Solomon B, Leyland-Jones B. Abstract P5-16-01: Implementation of routine genomic and proteomic profiling of metastatic breast cancer patients in a community cancer center. Cancer Res 2016. [DOI: 10.1158/1538-7445.sabcs15-p5-16-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: The optimal treatment strategy for patients with metastatic breast cancer (MBC) is currently unknown. Resistance to standard therapies, including anthracyclines and taxanes, limit the number of treatment options in many patients to a small number of non-cross resistant regimens. Rational combination approaches that are selected based upon genomic and proteomic analysis represents a possible advance that warrants extensive exploration.
Methods: Single center analysis of 77 consecutive metastatic breast cancer patients seen over a 12 month period (June 2014 through May 2015). All patients were referred for sequencing and the metastatic disease was rebiopsied. All samples were sent for standard pathologic, genomic (FoundationOne), and proteomic (TheraLink) analysis.
Results: Genomic and proteomic analysis yielded actionable targets in a majority of cases (89%). The most common pathways involved were the following: PI3K/Akt/mTOR (73%), MAPK (46%), ErbB (36%), FGFR (25%), and Jak/STAT (11%). Over 100 unique molecular aberrations were identified in 40 evaluable patients. Current outcomes are summarized in Table 1. The overall response rate was 45%, with another 43% of patients with stable disease. Average number of prior therapies was over 4, with a range of 1-11.
Table 1ER+/HER2-CR = 3PR = 8SD = 15PD = 2NE = 20ER+/HER2+CR = 2PR = 2SD = 1PD = 0NE = 9ER-/HER2+CR = 0PR = 1SD = 1PD = 1NE = 2Triple NegativeCR = 0PR = 2SD = 0PD = 2NE = 6Total evaluable patients = 40Overall CR = 13%Overall PR = 33%Overall SD = 43%Overall PD = 13%Total Not Evaluable = 37 pts (48%)Overall Response Rate (ORR) = 45% CR = complete response PR = partial response SD = stable disease PD = progressive disease NE = not evaluable
Conclusion: Since current literature suggests that an overall response rate of approximately 10% or less is expected for patients that have received greater than 4 previous lines of therapy, the ORR seen in this analysis is quite remarkable. Most patients in this analysis were treated with FDA approved drugs off label, which provided additional challenges and was the primary reason that many patients were not evaluable. Patients were only evaluable if they received the recommended therapy and were measured for outcome. Our initial data provides growing evidence that it is critical to incorporate genomic and proteomic analysis (preferably as early as possible in the disease course) to allow for the best chance of disease response.
Citation Format: Williams CB, Krie A, De P, Dey N, Klein J, Williams KA, Hoogeveen M, Solomon B, Leyland-Jones B. Implementation of routine genomic and proteomic profiling of metastatic breast cancer patients in a community cancer center. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-16-01.
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Affiliation(s)
| | - A Krie
- Avera Cancer Institute, Sioux Falls, SD
| | - P De
- Avera Cancer Institute, Sioux Falls, SD
| | - N Dey
- Avera Cancer Institute, Sioux Falls, SD
| | - J Klein
- Avera Cancer Institute, Sioux Falls, SD
| | | | | | - B Solomon
- Avera Cancer Institute, Sioux Falls, SD
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Gao W, Zhang Y, Ramanujan D, Ramani K, Chen Y, Williams CB, Wang CC, Shin YC, Zhang S, Zavattieri PD. The status, challenges, and future of additive manufacturing in engineering. Computer-Aided Design 2015; 69:65-89. [PMID: 0 DOI: 10.1016/j.cad.2015.04.001] [Citation(s) in RCA: 330] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Sirrine JM, Pekkanen AM, Nelson AM, Chartrain NA, Williams CB, Long TE. 3D-Printable Biodegradable Polyester Tissue Scaffolds for Cell Adhesion. Aust J Chem 2015. [DOI: 10.1071/ch15327] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Additive manufacturing, or three-dimensional (3D) printing, has emerged as a viable technique for the production of vascularized tissue engineering scaffolds. In this report, a biocompatible and biodegradable poly(tri(ethylene glycol) adipate) dimethacrylate was synthesized and characterized for suitability in soft-tissue scaffolding applications. The polyester dimethacrylate exhibited highly efficient photocuring, hydrolyzability, and 3D printability in a custom microstereolithography system. The photocured polyester film demonstrated significantly improved cell attachment and viability as compared with controls. These results indicate promise of novel, printable polyesters for 3D patterned, vascularized soft-tissue engineering scaffolds.
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Schultz AR, Lambert PM, Chartrain NA, Ruohoniemi DM, Zhang Z, Jangu C, Zhang M, Williams CB, Long TE. 3D Printing Phosphonium Ionic Liquid Networks with Mask Projection Microstereolithography. ACS Macro Lett 2014; 3:1205-1209. [PMID: 35610826 DOI: 10.1021/mz5006316] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photopolymerization coupled with mask projection microstereolithography successfully generated various 3D printed phosphonium polymerized ionic liquids (PILs) with low UV light intensity requirements and high digital resolution. Varying phosphonium monomer concentration, diacrylate cross-linking comonomer, and display images enabled precise 3D design and polymeric properties. The resulting cross-linked phosphonium PIL objects exhibited a synergy of high thermal stability, tunable glass transition temperature, optical clarity, and ion conductivity, which are collectively well-suited for emerging electro-active membrane technologies. Ion conductivity measurements on printed objects revealed a systematic progression in conductivity with ionic liquid monomer content, and thermal properties and solvent extraction demonstrated the formation of a polymerized ionic liquid network, with gel fractions exceeding 95%.
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Affiliation(s)
- Alison R. Schultz
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Philip M. Lambert
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Nicholas A. Chartrain
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - David M. Ruohoniemi
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Zhiyang Zhang
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Chainika Jangu
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Musan Zhang
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Christopher B. Williams
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Timothy E. Long
- Department of Mechanical
Engineering and ‡Macromolecular and Interfaces Institute,
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
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Sarles SA, Stiltner LJ, Williams CB, Leo DJ. Bilayer formation between lipid-encased hydrogels contained in solid substrates. ACS Appl Mater Interfaces 2010; 2:3654-3663. [PMID: 21067200 DOI: 10.1021/am100826s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Solidified biomolecular networks that incorporate liquid-supported lipid bilayers are constructed by attaching lipid-encased, water-swollen hydrogels contained in oil. Poly(ethylene glycol) dimethacrylate (PEG-DMA) and a free-radical photoinitiator are added to an aqueous lipid vesicle solution such that exposure to ultraviolet light results in solidification of neighboring aqueous volumes. Bilayer formation can occur both prior to photopolymerization with the aqueous mixture in the liquid state and after solidification by using the regulated attachment method (RAM) to attach the aqueous volumes contained within a flexible substrate. In addition, photopolymerization of the hydrogels can be performed in a separate mold prior to placement in the supporting substrate. Membranes formed across a wide range of hydrogel concentrations [0-80% (w/v); MW=1000 g/mol PEG-DMA] exhibit high electrical resistances (1-10 GΩ), which enable single-channel recordings of alamethicin channels and show significant durability and longevity. We demonstrate that just as liquid phases can be detached and reattached using RAM, reconfiguration of solid aqueous phases is also possible. The results presented herein demonstrate a step toward constructing nearly solid-state biomolecular materials that retain fluid interfaces for driving molecular assembly. This work also introduces the use of three-dimensional printing to rapidly prototype a molding template used to fabricate polyurethane substrates and to shape individual hydrogels.
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Affiliation(s)
- Stephen A Sarles
- Center for Intelligent Material Systems and Structures (CIMSS), Department of Mechanical Engineering, and Design, Research, and Education for Additive Manufacturing Systems (DREAMS) Laboratory, Virginia Tech, Blacksburg, Virginia 24061, United States
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Abstract
Data on individual daily feed intake, BW at 28-d intervals, and carcass composition were obtained on 1,212 crossbred steers. Within-animal regressions of cumulative feed intake and BW on linear and quadratic days on feed were used to quantify initial and ending BW, average daily observed feed intake (OFI), and ADG over a 120-d finishing period. Feed intake was predicted (PFI) with 3 biological simulation models (BSM): a) Decision Evaluator for the Cattle Industry, b) Cornell Value Discovery System, and c) NRC update 2000, using observed growth and carcass data as input. Residual feed intake (RFI) was estimated using OFI (RFI(EL)) in a linear statistical model (LSM), and feed conversion ratio (FCR) was estimated as OFI/ADG (FCR(E)). Output from the BSM was used to estimate RFI by using PFI in place of OFI with the same LSM, and FCR was estimated as PFI/ADG. These estimates were evaluated against RFI(EL) and FCR(E). In a second analysis, estimates of RFI were obtained for the 3 BSM as the difference between OFI and PFI, and these estimates were evaluated against RFI(EL). The residual variation was extremely small when PFI was used in the LSM to estimate RFI, and this was mainly due to the fact that the same input variables (initial BW, days on feed, and ADG) were used in the BSM and LSM. Hence, the use of PFI obtained with BSM as a replacement for OFI in a LSM to characterize individual animals for RFI was not feasible. This conclusion was also supported by weak correlations (<0.4) between RFI(EL) and RFI obtained with PFI in the LSM, and very weak correlations (<0.13) between RFI(EL) and FCR obtained with PFI. In the second analysis, correlations (>0.89) for RFI(EL) with the other RFI estimates suggest little difference between RFI(EL) and any of these RFI estimates. In addition, results suggest that the RFI estimates calculated with PFI would be better able to identify animals with low OFI and small ADG as inefficient compared with RFI(EL). These results may be due to the fact that computer models predict performance on an individual-animal basis in contrast to a LSM, which estimates a fixed relationship for all animals; hence, the BSM may provide RFI estimates that are closer to the true biological efficiency of animals. In addition, BSM may facilitate comparisons across different data sets and provide more accurate estimates of efficiency in small data sets where errors would be greater with a LSM.
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Affiliation(s)
- C B Williams
- USDA, ARS, US Meat Animal Research Center, Clay Center, NE 68933, USA.
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Abstract
BACKGROUND AND AIMS Poor standards in colonoscopy services and the introduction of a colorectal cancer screening program in the United Kingdom have highlighted the need to establish high-quality training and competency assessments in colonoscopy. The aims of this study were to evaluate the effectiveness of a 1-week hands-on colonoscopy course utilizing novel assessment tools. METHODS Twenty-one doctors with varying colonoscopy experience who attended an accelerated colonoscopy training week (ACTW) were prospectively studied. They were trained and assessed in key aspects of colonoscopy. Knowledge was assessed with a multiple choice question (MCQ) paper. Practical hand skills were taught and evaluated using a computer simulator and live case teaching. Actual colonoscopy performance was assessed using Direct Observation of Procedural Skills scores (DOPS) and an objective tri-split video score of insertion technique. Two independent trainers taught and assessed the trainees at the start and end of the ACTW and at a median of 9 months' follow-up. RESULTS Following training there were significant improvements in the MCQ score (P < 0.001), the simulator test case times (P = 0.02, P = 0.003), and the global DOPS score (P < or = 0.02). All improvements following the accelerated training were sustained at a median follow-up of 9 months. CONCLUSIONS This study is the first in the literature to describe the positive, sustained impact of an intensive hands-on colonoscopy training course. Measurements of performance in key areas of skill acquisition improved following training.
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Affiliation(s)
- S Thomas-Gibson
- Wolfson Unit for Endoscopy, St. Mark's Hospital, Harrow, Middlesex, UK.
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Williams CB, Bennett GL, Jenkins TG, Cundiff LV, Ferrell CL. Using simulation models to predict feed intake: phenotypic and genetic relationships between observed and predicted values in cattle. J Anim Sci 2006; 84:1310-6. [PMID: 16699087 DOI: 10.2527/2006.8461310x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The objectives of this study were to evaluate the accuracy of the Decision Evaluator for the Cattle Industry (DECI) and the Cornell Value Discovery System (CVDS) in predicting individual DMI and to assess the feasibility of using predicted DMI data in genetic evaluations of cattle. Observed individual animal data on the average daily DMI (OFI), ADG, and carcass measurements were obtained from postweaning records of 504 steers from 52 sires (502 with complete data). The experimental data and daily temperature and wind speed data were used as inputs to predict average daily feed DMI (kg) required (feed required; FR) for maintenance, cold stress, and ADG; maintenance and cold stress; ADG; maintenance and ADG; and maintenance alone, with CVDS (CFRmcg, CFRmc, CFRg, CFRmg, and CFRm, respectively) and DECI (DFRmcg, DFRmc, DFRg, DFRmg, and DFRm, respectively). Genetic parameters were estimated by REML using an animal model with age on test as a covariate and with genotype, age of dam, and year as fixed effects. Regression equations for observed on predicted DMI were OFI = 1.27 (SE = 0.27) + 0.83 (SE = 0.04) x CFRmcg [R2 = 0.44, residual SD (s(y.x)) = 0.669 kg/d] and OFI = 1.32 (SE = 0.22) + 0.8 (SE = 0.03) x DFRmcg (R2 = 0.53, s(y.x) = 0.612 kg/d). Heritability of OFI was 0.27 +/- 0.12, and heritabilities ranged from 0.33 +/- 0.12 to 0.41 +/- 0.13 for predicted measures of DMI. Phenotypic and genetic correlations between OFI and CFRmcg, CFRmc, CFRg, CFRmg, CFRm, DFRmcg, DFRmc, DFRg, DFRmg, and DFRm were 0.67, 0.73, 0.41, 0.63, 0.78, 0.73, 0.82, 0.45, 0.77, and 0.86 (P < 0.001 for all phenotypic correlations); and 0.95 +/- 0.07, 0.82 +/- 0.13, 0.89 +/- 0.09, 0.95 +/- 0.07, 0.91 +/- 0.09, 0.96 +/- 0.07, 0.89 +/- 0.09, 0.88 +/- 0.09, 0.96 +/- 0.06, and 0.96 +/- 0.07, respectively. Phenotypic and genetic correlations between CFRmcg and DFRmcg, CFRmc and DFRmc, CFRg and DFRg, CFRmg and DFRmg, and CFRm and DFRm were 0.98, 0.94, 0.99, 0.98, and 0.95 (P < 0.001 for all phenotypic correlations), and 0.99 +/- 0.004, 0.98 +/- 0.017, 0.99 +/- 0.004, 0.99 +/- 0.005, and 0.97 +/- 0.021, respectively. The strong genetic relationships between OFI and CFRmcg, CFRmg, DFRmcg, and DFRmg indicate that these predicted measures of DMI may be used in genetic evaluations and that DM requirements for cold stress may not be needed, thus reducing model complexity. However, high genetic correlations for final weight with OFI, CFRmcg, and DFRmcg suggest that the technology needs to be further evaluated in populations with genetic variance in feed efficiency.
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Affiliation(s)
- C B Williams
- USDA, ARS, US Meat Animal Research Center, Clay Center, NE, USA.
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Abstract
The authors hope that the combination of ScopeGuide imager (to make sense of colon looping) and the new-generation Colonoscopy Simulator (allowing structured teaching and repetitive practice) will make it possible to accelerate colonoscopy training and perhaps also will provide an acceptable way of re-honing the skills of existing endoscopists.
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Rutter MD, Saunders BP, Wilkinson KH, Rumbles S, Schofield G, Kamm MA, Williams CB, Price AB, Talbot IC, Forbes A. Thirty-year analysis of a colonoscopic surveillance program for neoplasia in ulcerative colitis. Gastroenterology 2006; 130:1030-8. [PMID: 16618396 DOI: 10.1053/j.gastro.2005.12.035] [Citation(s) in RCA: 432] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Accepted: 12/14/2005] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS The value of colonoscopic surveillance for neoplasia in long-standing extensive ulcerative colitis remains controversial. This study reports on prospectively collected data from a surveillance program over a 30-year period. METHODS Data were obtained from the prospective surveillance database, medical records, colonoscopy, and histology reports. The primary end point was defined as death, colectomy, withdrawal from surveillance, or census date (January 1, 2001). Follow-up information was obtained for patients who left the program. RESULTS Six hundred patients underwent 2627 colonoscopies during 5932 patient-years of follow-up. The cecal intubation rate was 98.7%, with no significant complications. Seventy-four patients (12.3%) developed neoplasia, including 30 colorectal cancers (CRCs). There was no difference in median age at onset of colitis for those with or without CRC (P = .8, Mann-Whitney). The cumulative incidence of CRC by colitis duration was 2.5% at 20 years, 7.6% at 30 years, and 10.8% at 40 years. The 5-year survival rate was 73.3%. Sixteen of 30 cancers were interval cancers. CRC incidence decreased over time (r = -.40, P = .04; linear regression). CONCLUSIONS Colonoscopic surveillance is safe and allows the vast majority of patients to retain their colon. Although two thirds of patients with potentially life-threatening neoplasia benefited from surveillance, the program was not wholly effective in cancer prevention. The cancer incidence, however, was considerably lower than in the majority of other studies, and was constant for up to 40 years of colitis duration, suggesting there is no need to intensify surveillance over time.
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Affiliation(s)
- Matthew D Rutter
- Department of Gastroenterology, University Hospital of North Tees, Stockton-on-Tees, Teesside, England.
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Abstract
Colorectal cancer is a common cancer and common cause of death. The mortality rate from colorectal cancer can be reduced by identification and removal of cancer precursors, adenomas, or by detection of cancer at an earlier stage. Pilot screening programmes have demonstrated decreased colorectal cancer mortality; as a result many countries are developing colorectal cancer screening programmes. The most common modalities being evaluated are faecal occult blood testing, flexible sigmoidoscopy and colonoscopy. Implementation of screening tests has been hampered by cost, invasiveness, availability of resources and patient acceptance. New technologies such at computed tomographic colonography and stool screening for molecular markers of neoplasia are in development as potential minimally invasive tools. This review considers who should be screened, which test to use and how often to screen.
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49
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Abstract
Colonoscopy traditionally has been taught using the apprenticeship approach. Assessment of competence has been, at best, informal and based largely on the number of procedures trainees have performed. The advent of colorectal cancer screening has demanded formalization of training and assessment using structured teaching and state-of-the-art training tools, such as computer simulation. New-generation approaches and technology have the ability to raise the standard of coloscopy provided by competent practitioners.
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Affiliation(s)
- Siwan Thomas-Gibson
- Wolfson Unit for Endoscopy, St. Mark's Hospital, Watford Road, Harrow, Middlesex HA1 3UJ, UK.
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50
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Abstract
Composition of empty BW (EBW) was described in terms of ether-extractable lipid (FAT) and fat-free matter (FFM), and the terms dEBW, dFAT, and dFFM were used to represent daily gains in these components. The dFFM comprised protein, water, and ash, and a model was developed to predict the composition of dFFM. The conceptual approach used in model development was based on experimental data that showed as cattle grew from birth to maturity: 1) the water content of FFM decreased and the protein and ash content increased; 2) the protein content of FFM increased at a decreasing rate; and 3) the protein-to-ash ratio in the fat-free DM was approximately constant. These results suggest that the protein content of dFFM would be high at birth and decrease at a decreasing rate as the animal grows. The protein content of dFFM was predicted as a function of the fraction of dEBW that was dFFM, FAT content of EBW, and dFFM. A fixed protein-to-ash ratio of 4.1:1 was used to calculate the quantity of ash, and water was obtained as a residual. Growth and body composition of Hereford x Angus steers from birth to 500 kg BW were simulated with a previously published model using the experimental growth data as input, and the model under discussion was used to predict the composition of dFFM. Predicted response curves of the EBW components over the growth period were similar in shape to observed data. Predicted curvilinearity in response of protein weight against FFM weight for Hereford x Angus steers was similar to observed data. The standard error about the regression of predicted on observed protein weight was 1.87 kg, and the average bias of the model was to underpredict protein weight by 0.64%. Compared with using a constant value for the protein fraction of dFFM, the model provided more accurate predictions of dEBW in an independent evaluation data set.
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Affiliation(s)
- C B Williams
- USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA.
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