1
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Calabrase W, Bishop LDC, Dutta C, Misiura A, Landes CF, Kisley L. Transforming Separation Science with Single-Molecule Methods. Anal Chem 2020; 92:13622-13629. [PMID: 32936608 DOI: 10.1021/acs.analchem.0c02572] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Empirical optimization of the multiscale parameters underlying chromatographic and membrane separations leads to enormous resource waste and production costs. A bottom-up approach to understand the physical phenomena underlying challenges in separations is possible with single-molecule observations of solute-stationary phase interactions. We outline single-molecule fluorescence techniques that can identify key interactions under ambient conditions. Next, we describe how studying increasingly complex samples heightens the relevance of single-molecule results to industrial applications. Finally, we illustrate how separation methods that have not been studied at the single-molecule scale can be advanced, using chiral chromatography as an example case. We hope new research directions based on a molecular approach to separations will emerge based on the ideas, technologies, and open scientific questions presented in this Perspective.
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Affiliation(s)
- William Calabrase
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Logan D C Bishop
- Department of Chemistry, Rice University, Houston, Texas 77251, United States
| | - Chayan Dutta
- Department of Chemistry, Rice University, Houston, Texas 77251, United States
| | - Anastasiia Misiura
- Department of Chemistry, Rice University, Houston, Texas 77251, United States
| | - Christy F Landes
- Department of Chemistry, Rice University, Houston, Texas 77251, United States.,Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251, United States.,Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251, United States.,Smalley-Curl Institute, Rice University, Houston, Texas 77251, United States
| | - Lydia Kisley
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, United States.,Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
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2
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Thompson CJ, Su Z, Vu VH, Wu Y, Leckband DE, Schwartz DK. Cadherin clusters stabilized by a combination of specific and nonspecific cis-interactions. eLife 2020; 9:e59035. [PMID: 32876051 PMCID: PMC7505656 DOI: 10.7554/elife.59035] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 09/01/2020] [Indexed: 12/13/2022] Open
Abstract
We demonstrate a combined experimental and computational approach for the quantitative characterization of lateral interactions between membrane-associated proteins. In particular, weak, lateral (cis) interactions between E-cadherin extracellular domains tethered to supported lipid bilayers, were studied using a combination of dynamic single-molecule Förster Resonance Energy Transfer (FRET) and kinetic Monte Carlo (kMC) simulations. Cadherins are intercellular adhesion proteins that assemble into clusters at cell-cell contacts through cis- and trans- (adhesive) interactions. A detailed and quantitative understanding of cis-clustering has been hindered by a lack of experimental approaches capable of detecting and quantifying lateral interactions between proteins on membranes. Here single-molecule intermolecular FRET measurements of wild-type E-cadherin and cis-interaction mutants combined with simulations demonstrate that both nonspecific and specific cis-interactions contribute to lateral clustering on lipid bilayers. Moreover, the intermolecular binding and dissociation rate constants are quantitatively and independently determined, demonstrating an approach that is generalizable for other interacting proteins.
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Affiliation(s)
- Connor J Thompson
- Department of Chemical and Biological Engineering, University of Colorado BoulderBoulderUnited States
| | - Zhaoqian Su
- Department of Systems and Computational Biology, Albert Einstein College of MedicineBronxUnited States
| | - Vinh H Vu
- Department of Biochemistry and University of Illinois, Urbana-ChampaignUrbanaUnited States
| | - Yinghao Wu
- Department of Systems and Computational Biology, Albert Einstein College of MedicineBronxUnited States
| | - Deborah E Leckband
- Department of Biochemistry and University of Illinois, Urbana-ChampaignUrbanaUnited States
- Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana-ChampaignUrbanaUnited States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado BoulderBoulderUnited States
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3
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Bolivar JM, Nidetzky B. On the relationship between structure and catalytic effectiveness in solid surface-immobilized enzymes: Advances in methodology and the quest for a single-molecule perspective. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2019; 1868:140333. [PMID: 31778816 DOI: 10.1016/j.bbapap.2019.140333] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 11/05/2019] [Accepted: 11/22/2019] [Indexed: 12/31/2022]
Abstract
The integration of enzymes with solid materials is important in many biotechnological applications, including the use of immobilized enzymes for biocatalytic synthesis. The development of functional enzyme-material composites is restrained by the lack of molecular-level insight into the behavior of enzymes in confined, surface-near environments. Here, we review recent advances in surface-sensitive spectroscopic techniques that push boundaries for the determination of enzyme structure and orientation at the solid-liquid interface. We discuss recent evidence from single-molecule studies showing that analyses sensitive to the temporal and spatial heterogeneities in immobilized enzymes can succeed in disentangling the effects of conformational stability and active-site accessibility on activity. Different immobilization methods involve distinct trade-off between these effects, thus emphasizing the need for a holistic (systems) view of immobilized enzymes for the rational development of practical biocatalysts.
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Affiliation(s)
- Juan M Bolivar
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, A-8010 Graz, Austria; Austrian Centre of Industrial Biotechnology, Petersgasse 12, A-8010 Graz, Austria; Chemical and Materials Engineering Department, Complutense University of Madrid, 28040 Madrid, Spain
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, A-8010 Graz, Austria; Austrian Centre of Industrial Biotechnology, Petersgasse 12, A-8010 Graz, Austria.
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4
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Dubrovin EV, Barinov NA, Schäffer TE, Klinov DV. In Situ Single-Molecule AFM Investigation of Surface-Induced Fibrinogen Unfolding on Graphite. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9732-9739. [PMID: 31282164 DOI: 10.1021/acs.langmuir.9b01178] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Fibrinogen adsorption plays a key role in important biological processes, such as blood coagulation and foreign body reaction, which determine the biocompatibility of a material. Fibrinogen conformation on a surface is one of the main factors triggering these processes. Understanding the conformational dynamics of fibrinogen molecules adsorbed on solid surfaces is, therefore, of great interest in biomedicine and may contribute to the development of new biomaterials. In this work, unfolding of fibrinogen molecules adsorbed on a model surface (highly oriented pyrolytic graphite modified with an oligoglycine-hydrocarbon graphite modifier) is directly visualized using time-lapse atomic force microscopy. A gradual transformation of native-like fibrinogen molecules into fibrillar structures is observed at a timescale of several minutes. This transformation is accompanied by a decrease in molecular height from 4-5 to 1-2 nm. Independent unfolding of different fibrinogen domains is demonstrated. The obtained results provide a new, direct insight into the unfolding of individual fibrinogen molecules on a surface and give new opportunities for the development of graphite-based biosensors and biomaterials.
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Affiliation(s)
- Evgeniy V Dubrovin
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency , Malaya Pirogovskaya, 1a , Moscow 119435 , Russian Federation
- Institute of Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
- Faculty of Physics , Lomonosov Moscow State University , Leninskie Gory, 1/2 , 119991 Moscow , Russian Federation
| | - Nikolay A Barinov
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency , Malaya Pirogovskaya, 1a , Moscow 119435 , Russian Federation
| | - Tilman E Schäffer
- Institute of Applied Physics , University of Tübingen , Auf der Morgenstelle 10 , 72076 Tübingen , Germany
| | - Dmitry V Klinov
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency , Malaya Pirogovskaya, 1a , Moscow 119435 , Russian Federation
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5
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Jansen LE, Amer LD, Chen EYT, Nguyen TV, Saleh LS, Emrick T, Liu WF, Bryant SJ, Peyton SR. Zwitterionic PEG-PC Hydrogels Modulate the Foreign Body Response in a Modulus-Dependent Manner. Biomacromolecules 2018; 19:2880-2888. [PMID: 29698603 PMCID: PMC6190668 DOI: 10.1021/acs.biomac.8b00444] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Reducing the foreign body response (FBR) to implanted biomaterials will enhance their performance in tissue engineering. Poly(ethylene glycol) (PEG) hydrogels are increasingly popular for this application due to their low cost, ease of use, and the ability to tune their compliance via molecular weight and cross-linking densities. PEG hydrogels can elicit chronic inflammation in vivo, but recent evidence has suggested that extremely hydrophilic, zwitterionic materials and particles can evade the immune system. To combine the advantages of PEG-based hydrogels with the hydrophilicity of zwitterions, we synthesized hydrogels with comonomers PEG and the zwitterion phosphorylcholine (PC). Recent evidence suggests that stiff hydrogels elicit increased immune cell adhesion to hydrogels, which we attempted to reduce by increasing hydrogel hydrophilicity. Surprisingly, hydrogels with the highest amount of zwitterionic comonomer elicited the highest FBR. Lowering the hydrogel modulus (165 to 3 kPa), or PC content (20 to 0 wt %), mitigated this effect. A high density of macrophages was found at the surface of implants associated with a high FBR, and mass spectrometry analysis of the proteins adsorbed to these gels implicated extracellular matrix, immune response, and cell adhesion protein categories as drivers of macrophage recruitment. Overall, we show that modulus regulates macrophage adhesion to zwitterionic-PEG hydrogels, and demonstrate that chemical modifications to hydrogels should be studied in parallel with their physical properties to optimize implant design.
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Affiliation(s)
| | - Luke D Amer
- Department of Chemical and Biological Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States
| | - Esther Y-T Chen
- Department of Biomedical Engineering , University of California, Irvine , Irvine , California 92697 , United States
| | | | - Leila S Saleh
- Department of Chemical and Biological Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States
| | | | - Wendy F Liu
- Department of Biomedical Engineering , University of California, Irvine , Irvine , California 92697 , United States
| | - Stephanie J Bryant
- Department of Chemical and Biological Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States
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6
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Faulón Marruecos D, Kienle DF, Kaar JL, Schwartz DK. Grafting Density Impacts Local Nanoscale Hydrophobicity in Poly(ethylene glycol) Brushes. ACS Macro Lett 2018; 7:498-503. [PMID: 35619349 DOI: 10.1021/acsmacrolett.8b00004] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Accumulated single-molecule observations of a fluorescent solvatochromic probe molecule were found to provide detailed local information about nanoscale hydrophobicity in polymer brushes. Using this approach, we showed that local hydrophobicity in poly(ethylene glycol) (PEG) brushes was spatially heterogeneous and increased with the surface grafting density of the polymer chains. These findings may provide an explanation for prior observations of the denaturation of surface-adsorbed proteins on PEG brushes with high grafting densities, which is believed to influence protein-mediated cell-surface interactions. Moreover, by employing the broad range of existing environmentally sensitive fluorophores, this approach may potentially be used to characterize nanoscale changes in a variety of physicochemical properties within polymeric materials.
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Affiliation(s)
- David Faulón Marruecos
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel F. Kienle
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Joel L. Kaar
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel K. Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
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7
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Moringo NA, Shen H, Bishop LDC, Wang W, Landes CF. Enhancing Analytical Separations Using Super-Resolution Microscopy. Annu Rev Phys Chem 2018; 69:353-375. [PMID: 29490205 DOI: 10.1146/annurev-physchem-052516-045018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Super-resolution microscopy is becoming an invaluable tool to investigate structure and dynamics driving protein interactions at interfaces. In this review, we highlight the applications of super-resolution microscopy for quantifying the physics and chemistry that occur between target proteins and stationary-phase supports during chromatographic separations. Our discussion concentrates on the newfound ability of super-resolved single-protein spectroscopy to inform theoretical parameters via quantification of adsorption-desorption dynamics, protein unfolding, and nanoconfined transport.
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Affiliation(s)
| | - Hao Shen
- Department of Chemistry, Rice University, Houston, Texas 77251, USA;
| | - Logan D C Bishop
- Department of Chemistry, Rice University, Houston, Texas 77251, USA;
| | - Wenxiao Wang
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251, USA
| | - Christy F Landes
- Department of Chemistry, Rice University, Houston, Texas 77251, USA; .,Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77251, USA.,Smalley-Curl Institute, Rice University, Houston, Texas 77251, USA
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8
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Moringo NA, Shen H, Tauzin LJ, Wang W, Bishop LDC, Landes CF. Variable Lysozyme Transport Dynamics on Oxidatively Functionalized Polystyrene Films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:10818-10828. [PMID: 28937222 DOI: 10.1021/acs.langmuir.7b02641] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Tuning protein adsorption dynamics at polymeric interfaces is of great interest to many biomedical and material applications. Functionalization of polymer surfaces is a common method to introduce application-specific surface chemistries to a polymer interface. In this work, single-molecule fluorescence microscopy is utilized to determine the adsorption dynamics of lysozyme, a well-studied antibacterial protein, at the interface of polystyrene oxidized via UV exposure and oxygen plasma and functionalized by ligand grafting to produce varying degrees of surface hydrophilicity, surface roughness, and induced oxygen content. Single-molecule tracking indicates lysozyme loading capacities, and surface mobility at the polymer interface is hindered as a result of all functionalization techniques. Adsorption dynamics of lysozyme depend on the extent and the specificity of the oxygen functionalities introduced to the polystyrene surface. Hindered adsorption and mobility are dominated by hydrophobic effects attributed to water hydration layer formation at the functionalized polystyrene surfaces.
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Affiliation(s)
- Nicholas A Moringo
- Department of Chemistry, ‡Department of Electrical and Computer Engineering, and §Smalley-Curl Institute, Rice University , Houston, Texas 77251, United States
| | - Hao Shen
- Department of Chemistry, ‡Department of Electrical and Computer Engineering, and §Smalley-Curl Institute, Rice University , Houston, Texas 77251, United States
| | - Lawrence J Tauzin
- Department of Chemistry, ‡Department of Electrical and Computer Engineering, and §Smalley-Curl Institute, Rice University , Houston, Texas 77251, United States
| | - Wenxiao Wang
- Department of Chemistry, ‡Department of Electrical and Computer Engineering, and §Smalley-Curl Institute, Rice University , Houston, Texas 77251, United States
| | - Logan D C Bishop
- Department of Chemistry, ‡Department of Electrical and Computer Engineering, and §Smalley-Curl Institute, Rice University , Houston, Texas 77251, United States
| | - Christy F Landes
- Department of Chemistry, ‡Department of Electrical and Computer Engineering, and §Smalley-Curl Institute, Rice University , Houston, Texas 77251, United States
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9
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Kastantin M, Faulón Marruecos D, Grover N, Yu McLoughlin S, Schwartz DK, Kaar JL. Connecting Protein Conformation and Dynamics with Ligand-Receptor Binding Using Three-Color Förster Resonance Energy Transfer Tracking. J Am Chem Soc 2017; 139:9937-9948. [PMID: 28658579 DOI: 10.1021/jacs.7b03978] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Specific binding between biomolecules, i.e., molecular recognition, controls virtually all biological processes including the interactions between cells and biointerfaces, both natural and synthetic. Such binding often relies on the conformation of biomacromolecules, which can be highly heterogeneous and sensitive to environmental perturbations, and therefore difficult to characterize and control. An approach is demonstrated here that directly connects the binding kinetics and stability of the protein receptor integrin αvβ3 to the conformation of the ligand fibronectin (FN), which are believed to control cellular mechanosensing. Specifically, we investigated the influence of surface-adsorbed FN structure and dynamics on αvβ3 binding using high-throughput single-molecule three-color Förster resonance energy transfer (FRET) tracking methods. By controlling FN structure and dynamics through tuning surface chemistry, we found that as the conformational and translational dynamics of FN increased, the rate of binding, particularly to folded FN, and stability of the bound FN-αvβ3 complex decreased significantly. These findings highlight the importance of the conformational plasticity and accessibility of the arginine-glycine-aspartic acid (RGD) binding site in FN, which, in turn, mediates cell signaling in physiological and synthetic environments.
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Affiliation(s)
- Mark Kastantin
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - David Faulón Marruecos
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Navdeep Grover
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Sean Yu McLoughlin
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Joel L Kaar
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
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10
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Kisley L, Miller KA, Guin D, Kong X, Gruebele M, Leckband DE. Direct Imaging of Protein Stability and Folding Kinetics in Hydrogels. ACS APPLIED MATERIALS & INTERFACES 2017; 9:21606-21617. [PMID: 28553706 DOI: 10.1021/acsami.7b01371] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We apply fast relaxation imaging (FReI) as a novel technique for investigating the folding stability and dynamics of proteins within polyacrylamide hydrogels, which have diverse and widespread uses in biotechnology. FReI detects protein unfolding in situ by imaging changes in fluorescence resonance energy transfer (FRET) after temperature jump perturbations. Unlike bulk measurements, diffraction-limited epifluorescence imaging combined with fast temperature perturbations reveals the impact of local environment effects on protein-biomaterial compatibility. Our experiments investigated a crowding sensor protein (CrH2) and phosphoglycerate kinase (PGK), which undergoes cooperative unfolding. The crowding sensor quantifies the confinement effect of the cross-linked hydrogel: the 4% polyacrylamide hydrogel is similar to aqueous solution (no confinement), while the 10% hydrogel is strongly confining. FRAP measurements and protein concentration gradients in the 4% and 10% hydrogels further support this observation. PGK reveals that noncovalent interactions of the protein with the polymer surface are more important than confinement for determining protein properties in the gel: the mere presence of hydrogel increases protein stability, speeds up folding relaxation, and promotes irreversible binding to the polymer even at the solution-gel interface, whereas the difference between the 4% and the 10% hydrogels is negligible despite their large difference in confinement. The imaging capabilities of FReI, demonstrated to be diffraction limited, further revealed spatially homogeneous protein unfolding across the hydrogels at 500 nm length scales and revealed differences in protein properties at the gel-solution boundary.
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Affiliation(s)
- Lydia Kisley
- Beckman Institute for Advanced Science and Technology, ‡Department of Chemistry, §Department of Biochemistry, ∥Department of Chemical and Biomolecular Engineering, and ⊥Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Kali A Miller
- Beckman Institute for Advanced Science and Technology, ‡Department of Chemistry, §Department of Biochemistry, ∥Department of Chemical and Biomolecular Engineering, and ⊥Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Drishti Guin
- Beckman Institute for Advanced Science and Technology, ‡Department of Chemistry, §Department of Biochemistry, ∥Department of Chemical and Biomolecular Engineering, and ⊥Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Xinyu Kong
- Beckman Institute for Advanced Science and Technology, ‡Department of Chemistry, §Department of Biochemistry, ∥Department of Chemical and Biomolecular Engineering, and ⊥Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Martin Gruebele
- Beckman Institute for Advanced Science and Technology, ‡Department of Chemistry, §Department of Biochemistry, ∥Department of Chemical and Biomolecular Engineering, and ⊥Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
| | - Deborah E Leckband
- Beckman Institute for Advanced Science and Technology, ‡Department of Chemistry, §Department of Biochemistry, ∥Department of Chemical and Biomolecular Engineering, and ⊥Department of Physics, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States
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11
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Faulón Marruecos D, Kastantin M, Schwartz DK, Kaar JL. Dense Poly(ethylene glycol) Brushes Reduce Adsorption and Stabilize the Unfolded Conformation of Fibronectin. Biomacromolecules 2016; 17:1017-25. [PMID: 26866385 DOI: 10.1021/acs.biomac.5b01657] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Polymer brushes, in which polymers are end-tethered densely to a grafting surface, are commonly proposed for use as stealth coatings for various biomaterials. However, although their use has received considerable attention, a mechanistic understanding of the impact of brush properties on protein adsorption and unfolding remains elusive. We investigated the effect of the grafting density of poly(ethylene glycol) (PEG) brushes on the interactions of the brush with fibronectin (FN) using high-throughput single-molecule tracking methods, which directly measure protein adsorption and unfolding within the brush. We observed that, as grafting density increased, the rate of FN adsorption decreased; however, surface-adsorbed FN unfolded more readily, and unfolded molecules were retained on the surface for longer residence times relative to those of folded molecules. These results, which are critical for the rational design of PEG brushes, suggest that there is a critical balance between protein adsorption and conformation that underlies the utility of such brushes in physiological environments.
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Affiliation(s)
- David Faulón Marruecos
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Mark Kastantin
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
| | - Joel L Kaar
- Department of Chemical and Biological Engineering, University of Colorado , Boulder, Colorado 80309, United States
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12
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Cai Y, Schwartz DK. Influence of Protein Surface Coverage on Anomalously Strong Adsorption Sites. ACS APPLIED MATERIALS & INTERFACES 2016; 8:511-520. [PMID: 26651508 DOI: 10.1021/acsami.5b09459] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Serum albumin is commonly used as a blocking agent to reduce nonspecific protein adsorption in bioassays and biodevices; however, the details of this process remain poorly understood. Using single molecule techniques, we investigated the dynamics of human serum albumin (HSA) on four model surfaces as a function of protein concentration. By constructing super-resolution maps, identifying anomalously strong adsorption sites, and quantifying surface heterogeneity, we found that the concentration required for site blocking varied dramatically with surface chemistry. When expressed in terms of protein surface coverage, however, a more consistent picture emerged, where a significant fraction of strong sites were passivated at a fractional coverage of 10(-4). On fused silica (FS), "non-fouling" oligo (ethylene glycol) functionalized FS, and hydrophobically modified FS, a modest additional site blocking effect continued at higher coverage. However, on amine-functionalized surfaces, the surface heterogeneity exhibited a minimum at a coverage of ∼10(-4). Using intermolecular Förster resonance energy transfer (FRET), we determined that new anomalous strong sites were created at higher coverage on amine surfaces and that adsorption to these sites was associated with protein-protein interactions, i.e., surface-induced aggregation.
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Affiliation(s)
- Yu Cai
- Department of Chemical and Biological Engineering, University of Colorado Boulder , 596 UCB, Boulder, Colorado 80309-0596, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder , 596 UCB, Boulder, Colorado 80309-0596, United States
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13
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Wang L, Li R, Li L, Wang H, Liu J. Study on the interaction between Fe 3+and fibrinogen and its influence on the polymerization behavior of fibrin networks. RSC Adv 2016. [DOI: 10.1039/c6ra17661e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The interactions between fibrinogen molecule and Fe3+were studied and applied to explicate the polymerization behavior of fibrinogen mediated with Fe3+. Overloading Fe3+in the fibrinogen solution will accelerate the amorphous aggregation of fibrin.
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Affiliation(s)
- Lei Wang
- Department of Chemistry
- Liaocheng University
- Liaocheng 252000
- China
| | - Rui Li
- Department of Chemistry
- Liaocheng University
- Liaocheng 252000
- China
| | - Lianzhi Li
- Department of Chemistry
- Liaocheng University
- Liaocheng 252000
- China
| | - Huaisheng Wang
- Department of Chemistry
- Liaocheng University
- Liaocheng 252000
- China
| | - Jifeng Liu
- Key Laboratory of Food Nutrition and Safety
- Ministry of Education of China
- Tianjin University of Science and Technology
- Tianjin 300457
- China
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