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Mehanna LE, Osborne AR, Peterson CA, Berron BJ. Spontaneous Alignment of Myotubes Through Myogenic Progenitor Cell Migration. Tissue Eng Part A 2024; 30:192-203. [PMID: 38019075 DOI: 10.1089/ten.tea.2023.0177] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023] Open
Abstract
In large-volume muscle injuries, widespread damage to muscle fibers and the surrounding connective tissue prevents myogenic progenitor cells (MPCs) from initiating repair. There is a clinical need to rapidly fabricate large muscle tissue constructs for integration at the site of large volume muscle injuries. Most strategies for myotube alignment require microfabricated structures or prolonged orientation times. We utilize the MPC's natural propensity to close gaps across an injury site to guide alignment on collagen I. When MPCs are exposed to an open boundary free of cells, they migrate unidirectionally into the cell-free region and align perpendicular to the original boundary direction. We study the utility of this phenomenon with biotin-streptavidin adhesion to position the cells on the substrate, and then demonstrate the robustness of this strategy with unmodified cells, creating a promising tool for MPC patterning without interrupting their natural function. We preposition MPCs in straight-line patterns separated with small gaps. This temporary positioning initiates the migratory nature of the MPCs to align and form myotubes across the gaps, similar to how they migrate and align with a single open boundary. There is a directional component to the MPC migration perpendicular (90°) to the original biotin-streptavidin surface patterns. The expression of myosin heavy chain, the motor protein of muscle thick filaments, is confirmed through immunocytochemistry in myotubes generated from MPCs in our patterning process, acting as a marker of skeletal muscle differentiation. The rapid and highly specific binding of biotin-streptavidin allows for quick formation of temporary patterns, with MPC alignment based on natural regenerative behavior rather than complex fabrication techniques.
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Affiliation(s)
- Lauren E Mehanna
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA
| | - Adrianna R Osborne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA
| | - Charlotte A Peterson
- Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Brad J Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA
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2
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Davis KA, Gottipatti A, Peng H, Donahue R, Chelvarajan L, Cahall C, Tripathi H, Al-Darraji A, Ye S, Abdel-Latif A, Berron BJ. Gelatin coating enhances therapeutic cell adhesion to the infarcted myocardium via ECM binding. PLoS One 2022; 17:e0277561. [PMID: 36355857 PMCID: PMC9648752 DOI: 10.1371/journal.pone.0277561] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 10/29/2022] [Indexed: 11/12/2022] Open
Abstract
Acute myocardial infarction (AMI) results in weakening of the heart muscle and an increased risk for chronic heart failure. Therapeutic stem cells have been shown to reduce inflammatory signaling and scar tissue expansion, despite most of these studies being limited by poor retention of cells. Gelatin methacrylate (GelMA) coatings have been shown to increase the retention of these therapeutic cells near the infarct. In this work, we evaluate two different potential binding partners for GelMA-coated bone marrow cells (BMCs) and myocardial tissue: the extracellular matrix (ECM) and interstitial non-cardiomyocytes. While cells containing β1 integrins mediate cell-ECM adhesion in vivo, these cells do not promote binding to our collagen-degraded, GelMA coating. Specifically, microscopic imagining shows that even with high integrin expression, GelMA-coated BMCs do not bind to cells within the myocardium. Alternatively, BMC incubation with decellularized heart tissue results in higher adhesion of coated cells versus uncoated cells supporting our GelMA-ECM binding mode. To further evaluate the ECM binding mode, cells were incubated on slides modified with one of three different major heart ECM components: collagen, laminin, or fibronectin. While all three components promoted higher adhesion than unmodified glass, collagen-coated slides resulted in a significantly higher adhesion of GelMA-coated BMCs over laminin and fibronectin. Incubation with unmodified BMCs confirmed that without a GelMA coating minimal adhesion of BMCs occurred. We conclude that GelMA cellular coatings significantly increase the binding of cells to collagen within the ECM. Our results provide progress towards a biocompatible and easily translatable method to enhance the retention of transplanted cells in human studies.
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Affiliation(s)
- Kara A. Davis
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, United States of America
| | - Anuhya Gottipatti
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, United States of America
| | - Hsuan Peng
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, United States of America
| | - Renee Donahue
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, United States of America
| | - Lakshman Chelvarajan
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, United States of America
| | - Calvin Cahall
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, United States of America
| | - Himi Tripathi
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, United States of America
| | - Ahmed Al-Darraji
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, United States of America
| | - Shaojing Ye
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, United States of America
| | - Ahmed Abdel-Latif
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, United States of America
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (BJB); (AAL)
| | - Brad J. Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, United States of America
- * E-mail: (BJB); (AAL)
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3
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Davis KA, Goh JZ, Sebastian AH, Ahern BM, Trinkle CA, Satin J, Abdel-Latif A, Berron BJ. Increased Retention of Cardiac Cells to a Glass Substrate through Streptavidin-Biotin Affinity. ACS Omega 2021; 6:17523-17530. [PMID: 34278138 PMCID: PMC8280672 DOI: 10.1021/acsomega.1c02003] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
In vitro analysis of primary isolated adult cardiomyocyte physiological processes often involves optical imaging of dye-loaded cells on a glass substrate. However, when exposed to rapid solution changes, primary cardiomyocytes often move to compromise quantitative measures. Improved immobilization of cells to glass would permit higher throughput assays. Here, we engineer the peripheral membrane of cardiomyocytes with biotin to anchor cardiomyocytes to borosilicate glass coverslips functionalized with streptavidin. We use a rat cardiac myoblast cell line to determine general relationships between processing conditions, ligand density on the cell and the glass substrate, cellular function, and cell retention under shear flow. Use of the streptavidin-biotin system allows for more than 80% retention of cardiac myoblasts under conventional rinsing procedures, while unmodified cells are largely rinsed away. The adhesion system enables the in-field retention of cardiac cells during rapid fluid changes using traditional pipetting or a modern microfluidic system at a flow rate of 160 mL/min. Under fluid flow, the surface-engineered primary adult cardiomyocytes are retained in the field of view of the microscope, while unmodified cells are rinsed away. Importantly, the engineered cardiomyocytes are functional following adhesion to the glass substrate, where contractions are readily observed. When applying this adhesion system to cardiomyocyte functional analysis, we measure calcium release transients by caffeine induction at an 80% success rate compared to 20% without surface engineering.
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Affiliation(s)
- Kara A. Davis
- Department
of Chemical and Materials Engineering, University
of Kentucky, Lexington, Kentucky 40506, United States
| | - Jensen Z. Goh
- Department
of Physiology, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Andrea H. Sebastian
- Department
of Physiology, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Brooke M. Ahern
- Department
of Physiology, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Christine A. Trinkle
- Department
of Mechanical Engineering, University of
Kentucky, Lexington, Kentucky 40506, United States
| | - Jonathan Satin
- Department
of Physiology, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Ahmed Abdel-Latif
- Gill
Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical
Center, Lexington, Kentucky 40506, United
States
| | - Brad J. Berron
- Department
of Chemical and Materials Engineering, University
of Kentucky, Lexington, Kentucky 40506, United States
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Davis K, Peng H, Chelvarajan L, Abdel-Latif A, Berron BJ. Increased yield of gelatin coated therapeutic cells through cholesterol insertion. J Biomed Mater Res A 2021; 109:326-335. [PMID: 32491263 PMCID: PMC7710926 DOI: 10.1002/jbm.a.37025] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 04/14/2020] [Accepted: 04/19/2020] [Indexed: 12/21/2022]
Abstract
Gelatin coatings are effective in increasing the retention of MSCs injected into the heart and minimizing the damage from acute myocardial infarction (AMI), but early studies suffered from low fractions of the MSCs coated with gelatin. Biotinylation of the MSC surface is a critical first step in the gelatin coating process, and in this study, we evaluated the use of biotinylated cholesterol "lipid insertion" anchors as a substitute for the covalent NHS-biotin anchors to the cell surface. Streptavidin-eosin molecules, where eosin is our photoinitiator, can then be bound to the cell surface through biotin-streptavidin affinity. The use of cholesterol anchors increased streptavidin density on the surface of MSCs further driving polymerization and allowing for an increased fraction of MSCs coated with gelatin (83%) when compared to NHS-biotin (52%). Additionally, the cholesterol anchors increased the uniformity of the coating on the MSC surface and supported greater numbers of coated MSCs even when the streptavidin density was slightly lower than that of an NHS-biotin anchoring strategy. Critically, this improvement in gelatin coating efficiency did not impact cytokine secretion and other critical MSC functions. Proper selection of the cholesterol anchor and the biotinylation conditions supports cellular function and densities of streptavidin on the MSC surface of up to ~105 streptavidin molecules/μm2 . In all, these cholesterol anchors offer an effective path towards the formation of conformal coatings on the majority of MSCs to improve the retention of MSCs in the heart following AMI.
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Affiliation(s)
- Kara Davis
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA
| | - Hsuan Peng
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky, Lexington KY, USA
| | - Lakshman Chelvarajan
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky, Lexington KY, USA
| | - Ahmed Abdel-Latif
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky, Lexington KY, USA
| | - Brad J. Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA
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5
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Peng H, Chelvarajan L, Donahue R, Gottipati A, Cahall CF, Davis KA, Tripathi H, Al-Darraji A, Elsawalhy E, Dobrozsi N, Srinivasan A, Levitan BM, Kong R, Gao E, Abdel-Latif A, Berron BJ. Polymer Cell Surface Coating Enhances Mesenchymal Stem Cell Retention and Cardiac Protection. ACS Appl Bio Mater 2021; 4:1655-1667. [PMID: 35014513 DOI: 10.1021/acsabm.0c01473] [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] [Indexed: 01/16/2023]
Abstract
Mesenchymal stem cell (MSC) therapy has been widely tested in clinical trials to promote healing post-myocardial infarction. However, low cell retention and the need for a large donor cell number in human studies remain a key challenge for clinical translation. Natural biomaterials such as gelatin are ideally suited as scaffolds to deliver and enhance cell engraftment after transplantation. A potential drawback of MSC encapsulation in the hydrogel is that the bulky matrix may limit their biological function and interaction with the surrounding tissue microenvironment that conveys important injury signals. To overcome this limitation, we adopted a gelatin methacrylate (gelMA) cell-coating technique that photocross-links gelatin on the individual cell surface at the nanoscale. The present study investigated the cardiac protection of gelMA coated, hypoxia preconditioned MSCs (gelMA-MSCs) in a murine myocardial infarction (MI) model. We demonstrate that the direct injection of gelMA-MSC results in significantly higher myocardial engraftment 7 days after MI compared to uncoated MSCs. GelMA-MSC further amplified MSC benefits resulting in enhanced cardioprotection as measured by cardiac function, scar size, and angiogenesis. Improved MSC cardiac retention also led to a greater cardiac immunomodulatory function after injury. Taken together, this study demonstrated the efficacy of gelMA-MSCs in treating cardiac injury with a promising potential to reduce the need for donor MSCs through enhanced myocardial engraftment.
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Affiliation(s)
- Hsuan Peng
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Lakshman Chelvarajan
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Renee Donahue
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Anuhya Gottipati
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Calvin F Cahall
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Kara A Davis
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Himi Tripathi
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Ahmed Al-Darraji
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Eman Elsawalhy
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Nicholas Dobrozsi
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Amrita Srinivasan
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Bryana M Levitan
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States.,Department of Physiology, University of Kentucky, Lexington, Kentucky 40508, United States
| | - Raymond Kong
- MilliporeSigma, Seattle, Washington 98119, United States
| | - Erhe Gao
- The Center for Translational Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, United States
| | - Ahmed Abdel-Latif
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, Kentucky 40508, United States
| | - Brad J Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
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6
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Gottipati A, Chelvarajan L, Peng H, Kong R, Cahall CF, Li C, Tripathi H, Al-Darraji A, Ye S, Elsawalhy E, Abdel-Latif A, Berron BJ. Gelatin Based Polymer Cell Coating Improves Bone Marrow-Derived Cell Retention in the Heart after Myocardial Infarction. Stem Cell Rev Rep 2020; 15:404-414. [PMID: 30644039 DOI: 10.1007/s12015-018-9870-5] [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] [Indexed: 12/21/2022]
Abstract
BACKGROUND Acute myocardial infarction (AMI) and the ensuing ischemic heart disease are approaching an epidemic state. Limited stem cell retention following intracoronary administration has reduced the clinical efficacy of this novel therapy. Polymer based cell coating is biocompatible and has been shown to be safe. Here, we assessed the therapeutic utility of gelatin-based biodegradable cell coatings on bone marrow derived cell retention in ischemic heart. METHODS Gelatin based cell coatings were formed from the surface-mediated photopolymerization of 3% gelatin methacrylamide and 1% PEG diacrylate. Cell coating was confirmed using a multimodality approach including flow cytometry, imaging flow cytometry (ImageStream System) and immunohistochemistry. Biocompatibility of cell coating, metabolic activity of coated cells, and the effect of cell coating on the susceptibility of cells for engulfment were assessed using in vitro models. Following myocardial infarction and GFP+ BM-derived mesenchymal stem cell transplantation, flow cytometric and immunohistochemical assessment of retained cells was performed. RESULTS Coated cells are viable and metabolically active with coating degrading within 72 h in vitro. Importantly, cell coating does not predispose bone marrow cells to aggregation or increase their susceptibility to phagocytosis. In vitro and in vivo studies demonstrated no evidence of heightened immune response or increased phagocytosis of coated cells. Cell transplantation studies following myocardial infarction proved the improved retention of coated bone marrow cells compared to uncoated cells. CONCLUSION Gelation based polymer cell coating is biologically safe and biodegradable. Therapies employing these strategies may represent an attractive target for improving outcomes of cardiac regenerative therapies in human studies.
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Affiliation(s)
- Anuhya Gottipati
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Lakshman Chelvarajan
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, USA
| | - Hsuan Peng
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, USA
| | | | - Calvin F Cahall
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Cong Li
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Himi Tripathi
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, USA
| | - Ahmed Al-Darraji
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, USA
| | - Shaojing Ye
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, USA
| | - Eman Elsawalhy
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, USA
| | - Ahmed Abdel-Latif
- Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky and the Lexington VA Medical Center, Lexington, KY, USA
| | - Brad J Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA.
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7
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Abstract
Injection into the heart tissue is a direct route for optimally placing mesenchymal stem cells (MSC) to regulate local inflammation following a heart attack. The retention of MSCs at the injection site is severely limited by the fluid flows that rapidly wash cells away and minimize their capacity to modulate cardiac inflammation. To prevent this loss of MSCs and their function, antibody coatings were designed for the surface of MSCs to enhance their adhesion to the inflamed tissue. MSCs were biotinylated, and biotinylated antibodies against intercellular cell adhesion molecules were conjugated to the cell surface through an intermediate layer of streptavidin. MSC surfaces were modified with ~7,000 biotin/μm2 and ~23 antibodies/μm2. The heart tissue injection of antibody-coated MSCs offered a 3-fold increase of cell retention in an infarcted heart over the injection of uncoated MSCs. We supported the mechanism of adhesion through analysis of MSC adhesion to inflamed endothelial cells and also surfaces of purified adhesion molecules on glass under microfluidic shear flow.
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Affiliation(s)
- Pei-Jung Wu
- Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, United States
| | - Hsuan Peng
- College of medicine, University of Kentucky, Lexington, Kentucky 40506-0046, United States
| | - Cong Li
- Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, United States
| | - Ahmed Abdel-Latif
- College of medicine, University of Kentucky, Lexington, Kentucky 40506-0046, United States
| | - Brad J Berron
- Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, United States
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Abstract
As the demand for organ transplants continues to grow faster than the supply of available donor organs, a new source of functional organs is needed. High resolution high throughput 3D bioprinting is one approach towards generating functional organs for transplantation. For high throughput printing, the need for increased print resolutions (by decreasing printing nozzle diameter) has a consequence: it increases the forces that cause cell damage during the printing process. Here, a novel cell encapsulation method provides mechanical protection from complete lysis of individual living cells during extrusion-based bioprinting. Cells coated in polymers possessing the mechanical properties finely-tuned to maintain size and shape following extrusion, and these encapsulated cells are protected from mechanical lysis. However, the shear forces imposed on the cells during extrusion still cause sufficient damage to compromise the cell membrane integrity and adversely impact normal cellular function. Cellular damage occurred during the extrusion process independent of the rapid depressurization.
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Affiliation(s)
- Calvin F Cahall
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Aman Preet Kaur
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Kara A Davis
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Jonathan T Pham
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Hainsworth Y Shin
- Division of Biology, Chemistry and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, 10903 New Hampshire Ave., Silver Spring, MD, 20993, USA
| | - Brad J Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
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9
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Torabi S, Li L, Grabau J, Sands M, Berron BJ, Xu R, Trinkle CA. Cassie-Baxter Surfaces for Reversible, Barrier-Free Integration of Microfluidics and 3D Cell Culture. Langmuir 2019; 35:10299-10308. [PMID: 31291112 PMCID: PMC6996068 DOI: 10.1021/acs.langmuir.9b01163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
3D cell culture and microfluidics both represent powerful tools for replicating critical components of the cell microenvironment; however, challenges involved in the integration of the two and compatibility with standard tissue culture protocols still represent a steep barrier to widespread adoption. Here we demonstrate the use of engineered surface roughness in the form of microfluidic channels to integrate 3D cell-laden hydrogels and microfluidic fluid delivery. When a liquid hydrogel precursor solution is pipetted onto a surface containing open microfluidic channels, the solid/liquid/air interface becomes pinned at sharp edges such that the hydrogel forms the "fourth wall" of the channels upon solidification. We designed Cassie-Baxter microfluidic surfaces that leverage this phenomenon, making it possible to have barrier-free diffusion between the channels and the hydrogel; in addition, sealing is robust enough to prevent leakage between the two components during fluid flow, but the sealing can also be reversed to facilitate recovery of the cell/hydrogel material after culture. This method was used to culture MDA-MB-231 cells in collagen, which remained viable and proliferated while receiving media exclusively through the microfluidic channels over the course of several days.
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Affiliation(s)
- Soroosh Torabi
- Mechanical Engineering , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Linzhang Li
- Pharmacology and Nutritional Sciences , University of Kentucky , Lexington , Kentucky 40536 , United States
- Markey Cancer Center , University of Kentucky , Lexington , Kentucky 40508 , United States
| | - Jonathan Grabau
- Mechanical Engineering , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Madison Sands
- Pharmacology and Nutritional Sciences , University of Kentucky , Lexington , Kentucky 40536 , United States
- Markey Cancer Center , University of Kentucky , Lexington , Kentucky 40508 , United States
| | - Brad J Berron
- Chemical and Materials Engineering , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Ren Xu
- Pharmacology and Nutritional Sciences , University of Kentucky , Lexington , Kentucky 40536 , United States
- Markey Cancer Center , University of Kentucky , Lexington , Kentucky 40508 , United States
| | - Christine A Trinkle
- Mechanical Engineering , University of Kentucky , Lexington , Kentucky 40506 , United States
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10
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Davis KA, Wu PJ, Cahall CF, Li C, Gottipati A, Berron BJ. Coatings on mammalian cells: interfacing cells with their environment. J Biol Eng 2019; 13:5. [PMID: 30675178 PMCID: PMC6337841 DOI: 10.1186/s13036-018-0131-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 12/09/2018] [Indexed: 12/18/2022] Open
Abstract
The research community is intent on harnessing increasingly complex biological building blocks. At present, cells represent a highly functional component for integration into higher order systems. In this review, we discuss the current application space for cellular coating technologies and emphasize the relationship between the target application and coating design. We also discuss how the cell and the coating interact in common analytical techniques, and where caution must be exercised in the interpretation of results. Finally, we look ahead at emerging application areas that are ideal for innovation in cellular coatings. In all, cellular coatings leverage the machinery unique to specific cell types, and the opportunities derived from these hybrid assemblies have yet to be fully realized.
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Affiliation(s)
- Kara A. Davis
- Chemical and Materials Engineering, University of Kentucky, 177 FPAT, Lexington, KY 40506-0046 USA
| | - Pei-Jung Wu
- Chemical and Materials Engineering, University of Kentucky, 177 FPAT, Lexington, KY 40506-0046 USA
| | - Calvin F. Cahall
- Chemical and Materials Engineering, University of Kentucky, 177 FPAT, Lexington, KY 40506-0046 USA
| | - Cong Li
- Chemical and Materials Engineering, University of Kentucky, 177 FPAT, Lexington, KY 40506-0046 USA
| | - Anuhya Gottipati
- Chemical and Materials Engineering, University of Kentucky, 177 FPAT, Lexington, KY 40506-0046 USA
| | - Brad J. Berron
- Chemical and Materials Engineering, University of Kentucky, 177 FPAT, Lexington, KY 40506-0046 USA
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11
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Lilly JL, Gottipati A, Cahall CF, Agoub M, Berron BJ. Comparison of eosin and fluorescein conjugates for the photoinitiation of cell-compatible polymer coatings. PLoS One 2018; 13:e0190880. [PMID: 29309430 PMCID: PMC5757926 DOI: 10.1371/journal.pone.0190880] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 12/21/2017] [Indexed: 12/17/2022] Open
Abstract
Targeted photopolymerization is the basis for multiple diagnostic and cell encapsulation technologies. While eosin is used in conjunction with tertiary amines as a water-soluble photoinitiation system, eosin is not widely sold as a conjugate with antibodies and other targeting biomolecules. Here we evaluate the utility of fluorescein-labeled bioconjugates to photopolymerize targeted coatings on live cells. We show that although fluorescein conjugates absorb approximately 50% less light energy than eosin in matched photopolymerization experiments using a 530 nm LED lamp, appreciable polymer thicknesses can still be formed in cell compatible environments with fluorescein photosensitization. At low photoinitiator density, eosin allows more sensitive initiation of gelation. However at higher functionalization densities, the thickness of fluorescein polymer films begins to rival that of eosin. Commercial fluorescein-conjugated antibodies are also capable of generating conformal, protective coatings on mammalian cells with similar viability and encapsulation efficiency as eosin systems.
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Affiliation(s)
- Jacob L. Lilly
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Anuhya Gottipati
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Calvin F. Cahall
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Mohamed Agoub
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Brad J. Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
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12
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Fursule IA, Abtahi A, Watkins CB, Graham KR, Berron BJ. In situ crosslinking of surface-initiated ring opening metathesis polymerization of polynorbornene for improved stability. J Colloid Interface Sci 2018; 510:86-94. [DOI: 10.1016/j.jcis.2017.09.050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 09/12/2017] [Accepted: 09/13/2017] [Indexed: 10/18/2022]
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13
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Abstract
Many naturally occurring cells possess an intrinsic ability to cross biological barriers that block conventional drug delivery, and these cells offer a possible mode of active transport across the blood-brain barrier or into the core of tumor masses. While many technologies for the formation of complete, nanoparticle-loaded coatings on cells exist, a complete coating on the cell surface would disrupt the interaction of cells with their environments. To address this issue, cell surface patches that partially cover cell surfaces might provide a superior approach for cell-mediated therapeutic delivery. The goal of this study is to establish a simplified approach to producing polymeric patches of arbitrary shapes on a live cell via surface-mediated photopolymerization. Cell surfaces were nonspecifically labeled with eosin, and polyethylene (glycol) diacrylate (PEGDA) coatings were directed to specific sites using 530 nm irradiation through a chrome-coated photomask. These coatings may entrap drug-loaded or imaging particles. The extent of nonspecific formation of PEGDA hydrogel coatings increased with irradiation time, light intensity, and initiating species; 40 mW/cm2 irradiation for 5 min delivered high-resolution patterns on the surface of A549 cells, and these cells remained viable for 48 h postpatterning with fluorescent nanoparticle-loaded coatings. This work first demonstrated the feasibility of photopatterning polymer patches directly on the surface of cells.
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Affiliation(s)
- Pei-Jung Wu
- Chemical and Materials Engineering, University of Kentucky , 153 FPAT, Lexington, Kentucky 40506-0046, United States
| | - Jacob L Lilly
- Chemical and Materials Engineering, University of Kentucky , 153 FPAT, Lexington, Kentucky 40506-0046, United States
| | - Roberto Arreaza
- Chemical and Materials Engineering, University of Kentucky , 153 FPAT, Lexington, Kentucky 40506-0046, United States
| | - Brad J Berron
- Chemical and Materials Engineering, University of Kentucky , 153 FPAT, Lexington, Kentucky 40506-0046, United States
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14
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Yu Y, Fursule IA, Mills LC, Englert DL, Berron BJ, Payne CM. CHARMM force field parameters for 2′-hydroxybiphenyl-2-sulfinate, 2-hydroxybiphenyl, and related analogs. J Mol Graph Model 2017; 72:32-42. [DOI: 10.1016/j.jmgm.2016.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 11/26/2022]
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15
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Zhou Q, Fursule I, Berron BJ, Beck MJ. Toward Spatiotemporally Controlled Synthesis of Photoresponsive Polymers: Computational Design of Azobenzene-Containing Monomers for Light-Mediated ROMP. J Phys Chem A 2016; 120:7101-11. [DOI: 10.1021/acs.jpca.6b05807] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Qunfei Zhou
- Department of Chemical and Materials Engineering and ‡Center for Computational
Sciences, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Ishan Fursule
- Department of Chemical and Materials Engineering and ‡Center for Computational
Sciences, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Brad J. Berron
- Department of Chemical and Materials Engineering and ‡Center for Computational
Sciences, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Matthew J. Beck
- Department of Chemical and Materials Engineering and ‡Center for Computational
Sciences, University of Kentucky, Lexington, Kentucky 40506, United States
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16
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Safazadeh L, Zehuri VEF, Pautler SP, Hastings JT, Berron BJ. Relative Contribution of Lateral Packing Density to Albumin Adsorption on Monolayers. Langmuir 2016; 32:8034-8041. [PMID: 27463892 DOI: 10.1021/acs.langmuir.6b01885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The effect of functional group density on protein adsorption is systematically studied to support ongoing efforts in molecular imprinting of surfaces and bulk materials. In these applications, functional commodity chemicals are molded to complement the shape and chemistry of the target molecule. Here, we study the relationship between bovine serum albumin adsorption and ligand density for carboxylate, alcohol, and alkyl terminal groups. Control surfaces consisting of densely packed self-assembled monolayers (SAMs) are contrasted with low-density SAMs formed through thiol-yne chemistry. Direct comparison consistently yielded greater protein adsorption on low-density SAMs than conventional pure component SAMs of the same functional group. Critically, the carboxylate and alcohol low-density SAMS are more hydrophobic than their analogous dense SAMs. Mixed functional group, dense SAMs were formed with alkyl diluents to match the hydrophobicity of the low-density SAMs. Once hydrophobicity is matched, the dense carboxylate and alcohol SAMs have higher adsorption than the low-density SAMs. We conclude (1) surface charge and hydrophobicity trends dominate over surface density contributions; (2) when hydrophobicity is matched, greater adsorption occurs on dense hydrophilic groups than on lower density hydrophilic groups; (3) when hydrophobicity is matched, greater adsorption occurs on lower density hydrophobic groups than on higher density hydrophobic groups.
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Affiliation(s)
| | | | - Samuel P Pautler
- Department of Bioengineering, University of Missouri , Columbia, Missouri 65211, United States
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17
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Abstract
Fluid biopsies potentially offer a minimally invasive alternative to traditional tissue biopsies for the continual monitoring of metastatic cancer. Current established technologies for isolating circulating tumor cells (CTCs) suffer from poor purity and yield and require fixatives that preclude the collection of viable cells for longitudinal analyses of biological function. Antigen specific lysis (ASL) is a rapid, high-purity method of cell isolation based on targeted protective coatings on antigen-presenting cells and lysis depletion of unprotected antigen-negative cells. In ASL, photoinitiators are specifically labeled on cell surfaces that enable subsequent surface-initiated polymerization. Critically, the significant determinants of process yield have yet to be investigated for this emerging technology. In this work, we show that the labeling density of photoinitiators is strongly correlated with the yield of intact cells during ASL by flow cytometry analysis. Results suggest ASL is capable of delivering ∼25% of targeted cells after isolation using traditional antibody labeling approaches. Monomer formulations of two molecular weights of PEG-diacrylate (Mn ∼ 575 and 3500) are examined. The gelation response during ASL polymerization is also investigated via protein microarray analogues on planar glass. Finally, a density threshold of photoinitiator labeling required for protection during lysis is determined for both monomer formulations. These results indicate ASL is a promising technology for high yield CTC isolation for rare-cell function assays and fluid biopsies.
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Affiliation(s)
- Jacob L Lilly
- Department of Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Brad J Berron
- Department of Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
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18
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Romero G, Lilly JJ, Abraham NS, Shin HY, Balasubramaniam V, Izumi T, Berron BJ. Protective Polymer Coatings for High-Throughput, High-Purity Cellular Isolation. ACS Appl Mater Interfaces 2015; 7:17598-602. [PMID: 26244409 PMCID: PMC4544319 DOI: 10.1021/acsami.5b06298] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cell-based therapies are emerging as the next frontier of medicine, offering a plausible path forward in the treatment of many devastating diseases. Critically, current methods for antigen positive cell sorting lack a high throughput method for delivering ultrahigh purity populations, prohibiting the application of some cell-based therapies to widespread diseases. Here we show the first use of targeted, protective polymer coatings on cells for the high speed enrichment of cells. Individual, antigen-positive cells are coated with a biocompatible hydrogel which protects the cells from a surfactant solution, while uncoated cells are immediately lysed. After lysis, the polymer coating is removed through orthogonal photochemistry, and the isolate has >50% yield of viable cells and these cells proliferate at rates comparable to control cells. Minority cell populations are enriched from erythrocyte-depleted blood to >99% purity, whereas the entire batch process requires 1 h and <$2000 in equipment. Batch scale-up is only contingent on irradiation area for the coating photopolymerization, as surfactant-based lysis can be easily achieved on any scale.
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Affiliation(s)
- Gabriela Romero
- Department of Chemical and Materials Engineering, Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Jacob J. Lilly
- Department of Chemical and Materials Engineering, Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Nathan S. Abraham
- Department
of Chemical Engineering, University of Massachusetts
Amherst, Amherst, Massachusetts 01003, United States
| | - Hainsworth Y. Shin
- Department of Chemical and Materials Engineering, Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Vivek Balasubramaniam
- Department
of Pediatrics, University of Wisconsin, Madison, Wisconsin 53792, United States
| | - Tadahide Izumi
- Graduate
Center for Toxicology, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Brad J. Berron
- Department of Chemical and Materials Engineering, Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
- E-mail:
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19
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Cahall CF, Lilly JL, Hirschowitz EA, Berron BJ. A Quantitative Perspective on Surface Marker Selection for the Isolation of Functional Tumor Cells. Breast Cancer (Auckl) 2015; 9:1-11. [PMID: 26309407 PMCID: PMC4517843 DOI: 10.4137/bcbcr.s25461] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/29/2015] [Accepted: 06/30/2015] [Indexed: 12/25/2022]
Abstract
Much effort has gone into developing fluid biopsies of patient peripheral blood for the monitoring of metastatic cancers. One common approach is to isolate and analyze tumor cells in the peripheral blood. Widespread clinical implementation of this approach has been hindered by the current choice of targeting epithelial markers known to be highly variable in primary tumor sites. Here, we review current antigen-based tumor cell isolation strategies and offer biological context for commonly studied cancer surface markers. Expression levels of the most common markers are quantitated for three breast cancer and two non-small cell lung cancer (NSCLC) lineage models. These levels are contrasted with that present on healthy peripheral blood mononuclear cells (PBMC) for comparison to expected background levels in a fluid biopsy setting. A key feature of this work is establishing a metric of markers per square micrometer. This describes an average marker density on the cell membrane surface, which is a critical metric for emerging isolation strategies. These results serve to extend expression of key tumor markers in a sensitive and dynamic manner beyond traditional positive/negative immunohistochemical staining to guide future fluid biopsy targeting strategies.
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Affiliation(s)
- Calvin F Cahall
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Jacob L Lilly
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Edward A Hirschowitz
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Kentucky Chandler Medical Center, Lexington, KY, USA
| | - Brad J Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
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20
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Abstract
Photoinitiated thiol-yne chemistry is utilized as a click reaction for grafting of acid-terminated alkynes to thiol-terminated monolayers on a gold substrate to create stable, low-density monolayers. The resulting monolayers are compared with a well-packed 11-mercaptoundecanoic acid monolayer and the analogous low-density monolayers prepared through a solution phase synthetic approach. The overall structuring of the monolayer prepared by solid-phase grafting is characterized by contact angle goniometry and Fourier transform infrared spectroscopy. The results show that the product monolayer has an intermediate surface energy and a more disordered chemical structuring compared to a traditional well-packed self-assembled monolayer, showing a low-packing density of the chains at the monolayer surface. The monolayer's structure and electrochemical stability were studied by reductive desorption of the thiolates. The prepared low-density monolayers have a higher electrochemical stability than traditional well-packed monolayers, which results from the crystalline structure at the gold interface. This technique allows for simple, fast preparation of low-density monolayers of higher stability than well-packed monolayers. The use of a photomask to restrict light access to the substrate yielded these low-density monolayers in patterned regions defined by light exposure. This general thiol-yne approach is adaptable to a variety of analogous low-density monolayers with diverse chemical functionalities.
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Affiliation(s)
- Leila Safazadeh
- Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506-0046, United States
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21
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Lilly JL, Romero G, Xu W, Shin HY, Berron BJ. Characterization of molecular transport in ultrathin hydrogel coatings for cellular immunoprotection. Biomacromolecules 2015; 16:541-9. [PMID: 25592156 DOI: 10.1021/bm501594x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PEG hydrogels are routinely used in immunoprotection applications to hide foreign cells from a host immune system. Size-dependent transport is typically exploited in these systems to prevent access by macromolecular elements of the immune system while allowing the transport of low molecular weight nutrients. This work studies a nanoscale hydrogel coating for improved transport of beneficial low molecular weight materials across thicker hydrogel coatings while completely blocking transport of undesired larger molecular weight materials. Coatings composed of PEG diacrylate of molecular weight 575 and 3500 Da were studied by tracking the transport of fluorescently labeled dextrans across the coatings. The molecular weight of dextran at which the transport is blocked by these coatings are consistent with cutoff values in analogous bulk PEG materials. Additionally, the diffusion constants of 4 kDa dextrans across PEG 575 coatings (9.5 × 10(-10)-2.0 × 10(-9) cm(2)/s) was lower than across PEG 3500 coatings (5.9-9.8 × 10(-9) cm(2)/s), and these trends and magnitudes agree with bulk scale models. Overall, these nanoscale thin PEG diacrylate films offer the same size selective transport behavior of bulk PEG diacrylate materials, while the lower thickness translates directly to increased flux of beneficial low molecular weight materials.
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Affiliation(s)
- Jacob L Lilly
- Department of Chemical and Materials Engineering and ∥Department of Biomedical Engineering, University of Kentucky , Lexington, Kentucky 40506, United States
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22
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Lilly JL, Sheldon PR, Hoversten LJ, Romero G, Balasubramaniam V, Berron BJ. Interfacial polymerization for colorimetric labeling of protein expression in cells. PLoS One 2014; 9:e115630. [PMID: 25536421 PMCID: PMC4275217 DOI: 10.1371/journal.pone.0115630] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 11/26/2014] [Indexed: 11/18/2022] Open
Abstract
Determining the location of rare proteins in cells typically requires the use of on-sample amplification. Antibody based recognition and enzymatic amplification is used to produce large amounts of visible label at the site of protein expression, but these techniques suffer from the presence of nonspecific reactivity in the biological sample and from poor spatial control over the label. Polymerization based amplification is a recently developed alternative means of creating an on-sample amplification for fluorescence applications, while not suffering from endogenous labels or loss of signal localization. This manuscript builds upon polymerization based amplification by developing a stable, archivable, and colorimetric mode of amplification termed Polymer Dye Labeling. The basic concept involves an interfacial polymer grown at the site of protein expression and subsequent staining of this polymer with an appropriate dye. The dyes Evans Blue and eosin were initially investigated for colorimetric response in a microarray setting, where both specifically stained polymer films on glass. The process was translated to the staining of protein expression in human dermal fibroblast cells, and Polymer Dye Labeling was specific to regions consistent with desired protein expression. The labeling is stable for over 200 days in ambient conditions and is also compatible with modern mounting medium.
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Affiliation(s)
- Jacob L. Lilly
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Phillip R. Sheldon
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Liv J. Hoversten
- Department of Pediatrics, University of Colorado, Denver, Colorado, United States of America
| | - Gabriela Romero
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
| | - Vivek Balasubramaniam
- Department of Pediatrics, University of Colorado, Denver, Colorado, United States of America
| | - Brad J. Berron
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail:
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23
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Stevens CA, Safazadeh L, Berron BJ. Thiol-yne adsorbates for stable, low-density, self-assembled monolayers on gold. Langmuir 2014; 30:1949-1956. [PMID: 24512439 DOI: 10.1021/la404940q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a novel approach toward carboxylate-terminated, low-density monolayers on gold, which provides exceptional adsorbate stability and conformational freedom of interfacial functional groups. Adsorbates are synthesized through the thiol-yne addition of two thiol-containing head groups to an alkyne-containing tail group. The resulting monolayers have two distinct phases: a highly crystalline head phase adjacent to the gold substrate, and a reduced density tail phase, which is in contact with the environment. The ellipsometric thickness of 27 Å is consistent with the proposed structure, where a densely packed decanedithiol monolayer is capped with an 11 carbon long, second layer at 50% lateral chain density. The Fourier transform infrared peak at 1710 cm(-1) supports the presence of the carbonyl group. Further, the peaks associated with asymmetric and symmetric methylene stretching are shifted toward higher wavenumbers compared to those of well-packed self-assembled monolayers (SAMs), which shows a lower average crystallinity of the thiol-yne monolayers compared to a typical monolayer. Contact angle measurements indicate an intermediate surface energy for the thiol-yne monolayer surface, owing to the contribution of exposed methylene functionality at the surface in addition to the carbonyl terminal group. The conformational freedom at the surface was demonstrated through remodeling the thiol-yne surface under an applied potential. Changes in the receding contact angle in response to an external potential support the capacity for reorientation of the surface presenting groups. Despite the low packing at the solution interface, thiol-yne monolayers are resistant to water and ion transport (R(f) ~ 10(5)), supporting the presence of a densely structured layer at the gold surface. Further, the electrochemical stability of the thiol-yne adsorbates exceeded that of well-packed SAMs, requiring a more reductive potential to desorb the thiol-yne monolayers from the gold surface. The thiol-yne monolayer approach is not limited to carboxylate functionality and is readily adapted for low-density monolayers of varied functionality.
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Affiliation(s)
- Christopher A Stevens
- Chemical and Materials Engineering, University of Kentucky , Lexington, Kentucky 40506-0046, United States
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24
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Abstract
The growing need for medical diagnostics in resource limited settings is driving the development of simple, standalone immunoassay devices. A capillary flow device using polymerization based amplification is capable of blocking a microfluidic channel in response to target biomaterials, enabling multiple modes of detection that require little or no supplemental instrumentation.
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Affiliation(s)
- Brad J. Berron
- Chemical and Biological Engineering, UCB 424, University of Colorado, Boulder, CO 80309, USA Fax: 3034924341; Tel: 303 492 3247
- Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Allison M. May
- Chemical and Biological Engineering, UCB 424, University of Colorado, Boulder, CO 80309, USA Fax: 3034924341; Tel: 303 492 3247
| | - Zheng Zheng
- Chemical and Biological Engineering, UCB 424, University of Colorado, Boulder, CO 80309, USA Fax: 3034924341; Tel: 303 492 3247
| | | | - Christopher N. Bowman
- Chemical and Biological Engineering, UCB 424, University of Colorado, Boulder, CO 80309, USA Fax: 3034924341; Tel: 303 492 3247
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25
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Avens HJ, Berron BJ, May AM, Voigt KR, Seedorf GJ, Balasubramaniam V, Bowman CN. Sensitive immunofluorescent staining of cells via generation of fluorescent nanoscale polymer films in response to biorecognition. J Histochem Cytochem 2011; 59:76-87. [PMID: 21339175 DOI: 10.1369/jhc.2010.955948] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Immunofluorescent staining is central to nearly all cell-based research, yet only a few fluorescent signal amplification approaches for cell staining exist, each with distinct limitations. Here, the authors present a novel, fluorescent polymerization-based amplification (FPBA) method that is shown to enable similar signal intensities as the highly sensitive, enzyme-based tyramide signal amplification (TSA) approach. Being non-enzymatic, FPBA is not expected to suffer from nonspecific staining of endogenous enzymes, as occurs with enzyme-based approaches. FPBA employs probes labeled with photopolymerization initiators, which lead to the controlled formation of fluorescent polymer films only at targeted biorecognition sites. Nuclear pore complex proteins (NPCs; in membranes), vimentin (in filaments), and von Willebrand factor (in granules) were all successfully immunostained by FPBA. Also, FPBA was demonstrated to be capable of multicolor immunostaining of multiple antigens. To assess relative sensitivity, decreasing concentrations of anti-NPC antibody were used, indicating that both FPBA and TSA stained NPC down to a 1:100,000 dilution. Nonspecific, cytoplasmic signal resulting from NPC staining was found to be reduced up to 5.5-fold in FPBA as compared to TSA, demonstrating better signal localization with FPBA. FPBA's unique approach affords a combination of preferred attributes, including high sensitivity and specificity not otherwise available with current techniques.
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Affiliation(s)
- Heather J Avens
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, CO 80309, USA
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26
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Berron BJ, Johnson LM, Ba X, McCall JD, Alvey NJ, Anseth KS, Bowman CN. Glucose oxidase-mediated polymerization as a platform for dual-mode signal amplification and biodetection. Biotechnol Bioeng 2011; 108:1521-8. [PMID: 21337335 PMCID: PMC3098304 DOI: 10.1002/bit.23101] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Revised: 01/31/2011] [Accepted: 02/07/2011] [Indexed: 11/22/2022]
Abstract
We report the first use of a polymerization-based ELISA substrate solution employing enzymatically mediated radical polymerization as a dual-mode amplification strategy. Enzymes are selectively coupled to surfaces to generate radicals that subsequently lead to polymerization-based amplification (PBA) and biodetection. Sensitivity and amplification of the polymerization-based detection system were optimized in a microwell strip format using a biotinylated microwell surface with a glucose oxidase (GOx)–avidin conjugate. The immobilized GOx is used to initiate polymerization, enabling the detection of the biorecognition event visually or through the use of a plate reader. Assay response is compared to that of an enzymatic substrate utilizing nitroblue tetrazolium in a simplified assay using biotinylated wells. The polymerization substrate exhibits equivalent sensitivity (2 µg/mL of GOx-avidin) and over three times greater signal amplification than this traditional enzymatic substrate since each radical that is enzymatically generated leads to a large number of polymerization events. Enzyme-mediated polymerization proceeds in an ambient atmosphere without the need for external energy sources, which is an improvement upon previous PBA platforms. Substrate formulations are highly sensitive to both glucose and iron concentrations at the lowest enzyme concentrations. Increases in amplification time correspond to higher assay sensitivities with no increase in non-specific signal. Finally, the polymerization substrate generated a signal to noise ratio of 14 at the detection limit (156 ng/mL) in an assay of transforming growth factor-beta. Biotechnol. Bioeng. 2011; 108:1521–1528. © 2011 Wiley Periodicals, Inc.
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Affiliation(s)
- Brad J Berron
- Department of Chemical and Biological Engineering, ECCH 111, UCB 424, University of Colorado, Boulder, Colorado 80309-0424, USA
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27
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Berron BJ, Faulkner CJ, Fischer RE, Payne PA, Jennings GK. Surface-initiated growth of ionomer films from pt-modified gold electrodes. Langmuir 2009; 25:12721-12728. [PMID: 19637878 DOI: 10.1021/la901809f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The ability to chemically wire ionomer films to electrode surfaces can promote transport near interfaces and impact a host of energy-related applications. Here, we demonstrate proof-of-concept principles for the surface-initiated ring-opening metathesis polymerization (SI-ROMP) of norbornene (NB), 5-butylnorbornene (NBH4), and 5-perfluorobutylnorbornene (NBF4) from Pt-modified gold substrates and the subsequent sulfonation of olefins along the polymer backbones to produce ultrathin sulfonated polymer films. Prior to sulfonation, the films are hydrophobic and exhibit large barriers against ion transport, but sulfonation dramatically reduces the resistance of the films by providing pathways for proton diffusion. Sulfonated films derived from NBF4 and NBH4 yield more anodic potentials for oxygen reduction than those derived from NB or unfunctionalized electrodes. These improvements are consistent with hydrophobic structuring by the fluorocarbon or hydrocarbon side groups to minimize interfacial flooding and generate pathways for enhanced O(2) permeation near the interface. Importantly, we demonstrate that the sulfonated polymer chains remain anchored to the surface during voltammetry for oxygen reduction whereas short-chain thiolates that do not tether polymer are removed from the substrate. This approach, which we extend to unmodified gold electrodes at neutral pH, presents a method of cleaning the ionomer/electrode interface to remove molecular components that may hamper the performance of the electrode.
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Affiliation(s)
- Brad J Berron
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
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28
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Ciesielski PN, Scott AM, Faulkner CJ, Berron BJ, Cliffel DE, Jennings GK. Functionalized nanoporous gold leaf electrode films for the immobilization of photosystem I. ACS Nano 2008; 2:2465-72. [PMID: 19206280 DOI: 10.1021/nn800389k] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants and some types of bacteria demonstrate an elegant means to capitalize on the superabundance of solar energy that reaches our planet with their energy conversion process called photosynthesis. Seeking to harness Nature's optimization of this process, we have devised a biomimetic photonic energy conversion system that makes use of the photoactive protein complex Photosystem I, immobilized on the surface of nanoporous gold leaf (NPGL) electrodes, to drive a photoinduced electric current through an electrochemical cell. The intent of this study is to further the understanding of how the useful functionality of these naturally mass-produced, biological light-harvesting complexes can be integrated with nonbiological materials. Here, we show that the protein complexes retain their photonic energy conversion functionality after attachment to the nanoporous electrode surface and, further, that the additional PSI/electrode interfacial area provided by the NPGL allows for an increase in PSI-mediated electron transfer with respect to an analogous 2D system if the pores are sufficiently enlarged by dealloying. This increase of interfacial area is pertinent for other applications involving electron transfer between phases; thus, we also report on the widely accessible and scalable method by which the NPGL electrode films used in this study are fabricated and attached to glass and Au/Si supports and demonstrate their adaptability by modification with various self-assembled monolayers. Finally, we demonstrate that the magnitude of the PSI-catalyzed photocurrents provided by the NPGL electrode films is dependent upon the intensity of the light used to irradiate the electrodes.
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Affiliation(s)
- Peter N Ciesielski
- Interdisciplinary Materials Science Program, Department of Chemistry, Vanderbilt University, Nashville, TN 37240, USA
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29
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Affiliation(s)
- Brad J. Berron
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235
| | - P. Andrew Payne
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235
| | - G. Kane Jennings
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235
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30
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Abstract
We report the surface-initiated growth of poly(alkylnorbornene) films via ring-opening metathesis polymerization (ROMP). The films are grown by exposure of a vinyl-terminated self-assembled monolayer (SAM) on gold to Grubbs first-generation catalyst and the subsequent exposure to an alkylnorbornene monomer. We investigate the influence of alkyl side chains on the structure, barrier, surface properties, and the growth kinetics of surface-initiated ROMP-type poly(norbornene) films. Rate constants for film growth are estimated for the comparison of monomer reactivity. The rate constant for film growth decreases by 3 orders of magnitude from norbornene to decylnorbornene, indicating a strong effect of chain length on initiation and/or propagation rates. Reflectance-absorption infrared spectroscopy is used to show the molecular level packing within the poly(alkylnorbornene) films is disrupted by the alkyl side chains. Tapping-mode atomic force microscopy is used to show that norbornene, butylnorbornene, and hexylnorbornene polymerize from the surface to form dense coatings, whereas decylnorbornene polymerizes to form isolated polymer clusters. The methyl terminus of the alkyl side chains increases the hydrophobicity of the poly(alkylnorbornene) films (thetaA(H2O) = 109-114 degrees) beyond that of a typical poly(norbornene) film (thetaA(H2O) approximately 106 degrees). The additional hydrophobicity throughout the film correlates with superior resistances against redox probes (Rf approximately 105 Omega.cm2) for poly(hexylnorbornene) when compared to polynorbornene (Rf approximately 104 Omega.cm2). The resistance of the poly(decylnorbornene) film (Rf approximately 102 Omega.cm2) is consistent with its nonuniform, cluster-like morphology.
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Affiliation(s)
- Brad J Berron
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
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31
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Abstract
We have investigated the effects of film composition and thickness on the rate of pH-induced response of a copolymer film containing predominately polymethylene with randomly distributed carboxylic acid side groups (denoted as PM-CO2H). These responsive films are prepared directly onto a gold electrode surface by surface-catalyzed polymerization and subsequent hydrolysis. We measured electrochemical impedance at fixed frequency (100 Hz) to monitor the barrier properties of the polymer film during a step change in pH. At a 1-3% molar acid content, the copolymer films exhibit a 2 order of magnitude change in impedance at 100 Hz when the contacting solution pH changes from 11 to 4 (or 4 to 11). For all films, the rate of protonation is slower than that of ionization, consistent with a more gradual transfer of protons through an increasingly hydrophobic film at the outermost nanometers during the protonation step. Increased acid content within the film accelerates both the rate of protonation and ionization. Thinner films (50 nm) with the same acid content show faster response rate in both directions, since water and ions have a shorter transfer path. A large and reversible pH response was obtained for all films studied, but selection of appropriate film composition and thickness can greatly influence the rate of response.
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Affiliation(s)
- Dongshun Bai
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235, USA
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