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McClendon MT, Ji W, Greene AC, Sai H, Sangji MH, Sather NA, Chen CH, Lee SS, Katchko K, Jeong SS, Kannan A, Weiner J, Cook R, Driscoll A, Lubbe R, Chang K, Haleem M, Chen F, Qiu R, Chun D, Stock SR, Hsu WK, Hsu EL, Stupp SI. A supramolecular polymer-collagen microparticle slurry for bone regeneration with minimal growth factor. Biomaterials 2023; 302:122357. [PMID: 37879188 PMCID: PMC10897953 DOI: 10.1016/j.biomaterials.2023.122357] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 05/10/2023] [Revised: 10/05/2023] [Accepted: 10/15/2023] [Indexed: 10/27/2023]
Abstract
Recombinant bone morphogenetic protein-2 (BMP-2) is a potent osteoinductive growth factor that can promote bone regeneration for challenging skeletal repair and even for ectopic bone formation in spinal fusion procedures. However, serious clinical side effects related to supraphysiological dosing highlight the need for advances in novel biomaterials that can significantly reduce the amount of this biologic. Novel biomaterials could not only reduce clinical side effects but also expand the indications for use of BMP-2, while at the same time lowering the cost of such procedures. To achieve this objective, we have developed a slurry containing a known supramolecular polymer that potentiates BMP-2 signaling and porous collagen microparticles. This slurry exhibits a paste-like consistency that stiffens into an elastic gel upon implantation making it ideal for minimally invasive procedures. We carried out in vivo evaluation of the novel biomaterial in the rabbit posterolateral spine fusion model, and discovered efficacy at unprecedented ultra-low BMP-2 doses (5 μg/implant). This dose reduces the growth factor requirement by more than 100-fold relative to current clinical products. This observation is significant given that spinal fusion involves ectopic bone formation and the rabbit model is known to be predictive of human efficacy. We expect the novel biomaterial can expand BMP-2 indications for difficult cases requiring large volumes of bone formation or involving patients with underlying conditions that compromise bone regeneration.
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Affiliation(s)
- Mark T McClendon
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States
| | - Wei Ji
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States
| | - Allison C Greene
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Hiroaki Sai
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States
| | - M Hussain Sangji
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, United States
| | - Nicholas A Sather
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States
| | - Charlotte H Chen
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States
| | - Sungsoo S Lee
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States
| | - Karina Katchko
- Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Soyeon Sophia Jeong
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Abhishek Kannan
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Joseph Weiner
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Ralph Cook
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Adam Driscoll
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Ryan Lubbe
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Kevin Chang
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Meraaj Haleem
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Feng Chen
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States
| | - Ruomeng Qiu
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Chemistry, Northwestern University, Evanston, IL, 60208, United States
| | - Danielle Chun
- Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Stuart R Stock
- Department of Cell and Molecular Biology, Northwestern University, Chicago, IL, 60611, United States
| | - Wellington K Hsu
- Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Erin L Hsu
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Orthopaedic Surgery, Northwestern University, Chicago, IL, 60611, United States
| | - Samuel I Stupp
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL, 60611, United States; Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, United States; Department of Chemistry, Northwestern University, Evanston, IL, 60208, United States; Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, United States; Department of Medicine, Northwestern University, Chicago, IL, 60611, United States.
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Li C, Xiong Q, Clemons TD, Sai H, Yang Y, Hussain Sangji M, Iscen A, Palmer LC, Schatz GC, Stupp SI. Role of supramolecular polymers in photo-actuation of spiropyran hydrogels. Chem Sci 2023; 14:6095-6104. [PMID: 37293659 PMCID: PMC10246702 DOI: 10.1039/d3sc00401e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/14/2023] [Indexed: 06/10/2023] Open
Abstract
Supramolecular-covalent hybrid polymers have been shown to be interesting systems to generate robotic functions in soft materials in response to external stimuli. In recent work supramolecular components were found to enhance the speed of reversible bending deformations and locomotion when exposed to light. The role of morphology in the supramolecular phases integrated into these hybrid materials remains unclear. We report here on supramolecular-covalent hybrid materials that incorporate either high-aspect-ratio peptide amphiphile (PA) ribbons and fibers, or low-aspect-ratio spherical peptide amphiphile micelles into photo-active spiropyran polymeric matrices. We found that the high-aspect-ratio morphologies not only play a significant role in providing mechanical reinforcement to the matrix but also enhance photo-actuation for both light driven volumetric contraction and expansion of spiropyran hydrogels. Molecular dynamics simulations indicate that water within the high-aspect-ratio supramolecular polymers exhibits a faster draining rate as compared to those in spherical micelles, which suggests that the high-aspect-ratio supramolecular polymers effectively facilitate the transport of trapped water molecules by functioning as channels and therefore enhancing actuation of the hybrid system. Our simulations provide a useful strategy for the design of new functional hybrid architectures and materials with the aim of accelerating response and enhancing actuation by facilitating water diffusion at the nanoscopic level.
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Affiliation(s)
- Chuang Li
- Department of Polymer Science and Engineering, University of Science and Technology of China Hefei Anhui 230026 China
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Qinsi Xiong
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Tristan D Clemons
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Hiroaki Sai
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Materials Science and Engineering, Northwestern University 2220 Campus Drive Evanston IL 60208 USA
| | - Yang Yang
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - M Hussain Sangji
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Biomedical Engineering, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Aysenur Iscen
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Chemical and Biological Engineering, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Liam C Palmer
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Simpson Querrey Institute, Northwestern University 303 E. Superior Street Chicago IL 60611 USA
| | - George C Schatz
- Department of Chemical and Biological Engineering, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
| | - Samuel I Stupp
- Center for Bio-inspired Energy Science, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Chemistry, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Materials Science and Engineering, Northwestern University 2220 Campus Drive Evanston IL 60208 USA
- Department of Biomedical Engineering, Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
- Department of Medicine, Northwestern University 676 N St. Clair Chicago IL 60611 USA
- Simpson Querrey Institute, Northwestern University 303 E. Superior Street Chicago IL 60611 USA
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Dumele O, Đorđević L, Sai H, Cotey TJ, Sangji MH, Sato K, Dannenhoffer AJ, Stupp SI. Photocatalytic Aqueous CO 2 Reduction to CO and CH 4 Sensitized by Ullazine Supramolecular Polymers. J Am Chem Soc 2022; 144:3127-3136. [PMID: 35143726 DOI: 10.1021/jacs.1c12155] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
There has been rapid progress on the chemistry of supramolecular scaffolds that harness sunlight for aqueous photocatalytic production of hydrogen. However, great efforts are still needed to develop similar photosynthetic systems for the great challenge of CO2 reduction especially if they avoid the use of nonabundant metals. This work investigates the synthesis of supramolecular polymers capable of sensitizing catalysts that require more negative potentials than proton reduction. The monomers are chromophore amphiphiles based on a diareno-fused ullazine core that undergo supramolecular polymerization in water to create entangled nanoscale fibers. Under 450 nm visible light these fibers sensitize a dinuclear cobalt catalyst for CO2 photoreduction to generate carbon monoxide and methane using a sacrificial electron donor. The supramolecular photocatalytic system can generate amounts of CH4 comparable to those obtained with a precious metal-based [Ru(phen)3](PF6)2 sensitizer and, in contrast to Ru-based catalysts, retains photocatalytic activity in all aqueous media over 6 days. The present study demonstrates the potential of tailored supramolecular polymers as renewable energy and sustainability materials.
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Affiliation(s)
- Oliver Dumele
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Luka Đorđević
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois 60611, United States
| | - Hiroaki Sai
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Thomas J Cotey
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - M Hussain Sangji
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Kohei Sato
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois 60611, United States
| | - Adam J Dannenhoffer
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Samuel I Stupp
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.,Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States.,Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois 60611, United States.,Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States.,Department of Medicine, Northwestern University, Chicago, Illinois 60611, United States
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Godbe JM, Freeman R, Lewis JA, Sasselli IR, Sangji MH, Stupp SI. Hydrogen Bonding Stiffens Peptide Amphiphile Supramolecular Filaments by Aza-Glycine Residues. Acta Biomater 2021; 135:87-99. [PMID: 34481055 DOI: 10.1016/j.actbio.2021.08.044] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 12/30/2022]
Abstract
Peptide amphiphiles (PAs) are a class of molecules comprised of short amino acid sequences conjugated to hydrophobic moieties that may exhibit self-assembly in water into supramolecular structures. We investigate here how mechanical properties of hydrogels formed by PA supramolecular nanofibers are affected by hydrogen bond densities within their internal structure by substituting glycine for aza-glycine (azaG) residues. We found that increasing the number of PA molecules that contain azaG up to 5 mol% in PA supramolecular nanofibers increases their persistence length fivefold and decreases their diffusion coefficients as measured by fluorescence recovery after photobleaching. When these PAs are used to create hydrogels, their bulk storage modulus (G') was found to increase as azaG PA content in the supramolecular assemblies increases up to a value of 10 mol% and beyond this value a decrease was observed, likely due to diminished levels of nanofiber entanglement in the hydrogels as a direct result of increased supramolecular rigidity. Interestingly, we found that the bioactivity of the scaffolds toward dopaminergic neurons derived from induced pluripotent stem cells can be enhanced directly by persistence length independently of storage modulus. We hypothesize that this is due to interactions between the cells and the extracellular environment across different size scales: from filopodia adhering to individual nanofiber bundles to cell adhesion sites that interact with the hydrogel as a bulk substrate. Fine tuning of hydrogen bond density in self-assembling peptide biomaterials such as PAs provides an approach to control nanoscale stiffness as part of an overall strategy to optimize bioactivity in these supramolecular systems. supramolecular biomaterials. STATEMENT OF SIGNIFICANCE: Hydrogen bonding is an important driving force for the self-assembly of peptides in both biological and artificial systems. Here, we increase the amount of hydrogen bonding within self-assembled peptide amphiphile (PA) nanofibers by substituting glycine for an aza-glycine (azaG). We show that increasing the molar concentration of azaG increases the internal order of individual nanofibers and increases their persistence length. We also show that these changes are sufficient to increase survival and tyrosine hydroxylase expression in induced pluripotent stem cell-derived dopaminergic neurons cultured in 3D gels made of these materials. Our strategy of tuning the number of hydrogen bonds in a supramolecular assembly provides mechanical customization for 3D cell culture and tissue engineering.
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Affiliation(s)
- Jacqueline M Godbe
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 E. Superior St, Chicago, Illinois 60611, United States; Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Ronit Freeman
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 E. Superior St, Chicago, Illinois 60611, United States
| | - Jacob A Lewis
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 E. Superior St, Chicago, Illinois 60611, United States; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Ivan R Sasselli
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - M Hussain Sangji
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Samuel I Stupp
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 E. Superior St, Chicago, Illinois 60611, United States; Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States; Department of Medicine, Northwestern University, 676 N St Clair St Suite 1600, Chicago, IL 60611, United States; Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States.
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5
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Sangji MH, Sai H, Chin SM, Lee SR, Sasselli IR, Palmer LC, Stupp SI. Correction to "Supramolecular Interactions and Morphology of Self-Assembling Peptide Amphiphile Nanostructures". Nano Lett 2021; 21:7427-7428. [PMID: 34460253 DOI: 10.1021/acs.nanolett.1c03116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- M Hussain Sangji
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Hiroaki Sai
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Stacey M Chin
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Sieun Ruth Lee
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Ivan R Sasselli
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
| | - Liam C Palmer
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Samuel I Stupp
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Medicine, Northwestern University, 676 N St. Clair, Chicago, Illinois 60611, United States
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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Sangji MH, Sai H, Chin SM, Lee SR, R Sasselli I, Palmer LC, Stupp SI. Supramolecular Interactions and Morphology of Self-Assembling Peptide Amphiphile Nanostructures. Nano Lett 2021; 21:6146-6155. [PMID: 34259001 DOI: 10.1021/acs.nanolett.1c01737] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The morphology of supramolecular peptide nanostructures is difficult to predict given their complex energy landscapes. We investigated peptide amphiphiles containing β-sheet forming domains that form twisted nanoribbons in water. We explained the morphology based on a balance between the energetically favorable packing of molecules in the center of the nanostructures, the unfavorable packing at the edges, and the deformations due to packing of twisted β-sheets. We find that morphological polydispersity of PA nanostructures is determined by peptide sequences, and the twisting of their internal β-sheets. We also observed a change in the supramolecular chirality of the nanostructures as the peptide sequence was modified, although only amino acids with l-configuration were used. Upon increasing charge repulsion between molecules, we observed a change in morphology to long cylinders and then rodlike fragments and spherical micelles. Understanding the self-assembly mechanisms of peptide amphiphiles into nanostructures should be useful to optimize their well-known functions.
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Affiliation(s)
- M Hussain Sangji
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Hiroaki Sai
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Stacey M Chin
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Sieun Ruth Lee
- Department of Materials Science and Engineering, 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Ivan R Sasselli
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
| | - Liam C Palmer
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Samuel I Stupp
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering, 2220 Campus Drive, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Medicine, Northwestern University, 676 N St. Clair, Chicago, Illinois 60611, United States
- Simpson Querrey Institute, Northwestern University, 303 E Superior, Chicago, Illinois 60611, United States
- Center for Bio-Inspired Energy Science, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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Anthonisen M, Zhang Y, Hussain Sangji M, Grütter P. Quantifying bio-filament morphology below the diffraction limit of an optical microscope using out-of-focus images. Appl Opt 2020; 59:2914-2923. [PMID: 32225847 DOI: 10.1364/ao.388265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 02/24/2020] [Indexed: 06/10/2023]
Abstract
A method to measure the dimensions of objects below the optical diffraction limit using diffraction analysis of out-of-focus bright-field images is presented. The method relies on the comparison of the diffraction patterns of an object of unknown size to those of calibration objects of known size. Correlative scanning electron microscope measurements are used to demonstrate the applicability of this method to measure 100 nm microbeads as well as objects with a geometry different from the calibration objects. This technique is important in the context of tethered particle experiments, in which bio-filaments are bound between a substrate and a microbead. This procedure is applied to obtain the diameters of axonal extensions or neurites that are mechanically created in samples of rat hippocampal neurons. The dependence of neurite geometry on mechanical pull speed is investigated, and the diameter is found to be rate independent.
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