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Rahimi E, Imani A, Kim D, Rahimi M, Fedrizzi L, Mol A, Asselin E, Pané S, Lekka M. Physicochemical Changes of Apoferritin Protein during Biodegradation of Magnetic Metal Oxide Nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2024; 16:53299-53310. [PMID: 39288080 PMCID: PMC11450718 DOI: 10.1021/acsami.4c12269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2024] [Revised: 09/03/2024] [Accepted: 09/09/2024] [Indexed: 09/19/2024]
Abstract
The biodegradation of therapeutic magnetic-oxide nanoparticles (MONPs) in the human body raises concerns about their lifespan, functionality, and health risks. Interactions between apoferritin proteins and MONPs in the spleen, liver, and inflammatory macrophages significantly accelerate nanoparticle degradation, releasing metal ions taken up by apoferritin. This can alter the protein's biological structure and properties, potentially causing health hazards. This study examines changes in apoferritin's shape, electrical surface potential (ESP), and protein-core composition after incubation with cobalt-ferrite (CoFe2O4) oxide nanoparticles. Using atomic force microscopy (AFM) and scanning Kelvin probe force microscopy (SKPFM), we observed changes in the topography and ESP distribution in apoferritin nanofilms over time. After 48 h, the characteristic apoferritin hole (∼1.35 nm) vanished, and the protein's height increased from ∼3.5 to ∼7.5 nm due to hole filling. This resulted in a significant ESP increase on the filled-apoferritin surface, attributed to the formation of a heterogeneous chemical composition and crystal structure (γ-Fe2O3, Fe3O4, CoO, CoOOH, FeOOH, and Co3O4). These changes enhance electrostatic interactions and surface charge between the protein and the AFM tip. This approach aids in predicting and improving the MONP lifespan while reducing their toxicity and preventing apoferritin deformation and dysfunction.
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Affiliation(s)
- Ehsan Rahimi
- Department
of Materials Science and Engineering, Delft
University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Amin Imani
- Department
of Materials Engineering, The University
of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Donghoon Kim
- Laboratory
for Multiscale Materials Experiments, Paul
Scherrer Institute, Forschungstrasse 111, Villigen 5232, Switzerland
| | - Mohammad Rahimi
- Department
of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 3L8, Canada
| | - Lorenzo Fedrizzi
- Polytechnic
Department of Engineering and Architecture, University of Udine, 33100 Udine, Italy
| | - Arjan Mol
- Department
of Materials Science and Engineering, Delft
University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Edouard Asselin
- Department
of Materials Engineering, The University
of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Salvador Pané
- Multi-Scale
Robotics Lab, Institute of Robotics and Intelligent Systems, Department
of Mechanical and Process Engineering, ETH
Zurich, Tannenstrasse 3, Zurich 8092, Switzerland
| | - Maria Lekka
- CIDETEC,
Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián 20014, Spain
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Davantès A, Nigen M, Sanchez C, Renard D. Adsorption of Acacia Gum on Self-Assembled Monolayer Surfaces: A Comprehensive Study Using QCM-D and MP-SPR. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:19032-19042. [PMID: 39206803 DOI: 10.1021/acs.langmuir.4c02002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The interfacial structuring of Acacia gum at various pH values on self-assembled monolayer (SAM) surfaces was investigated in order to evaluate the respective importance of surface versus biopolymer hydration in the adsorption process of the gum. To this end, SAMs with four different ending chemical functionalities (-CH3, -OH, -COOH, and -NH2) were used on gold surfaces, and the gum adsorption was monitored using multiparametric surface plasmon resonance (MP-SPR) and quartz crystal microbalance with dissipation. Surface modification with alkanethiol and the subsequent adsorption of Acacia gum were also characterized by contact angle measurements using both sessile drop and captive bubble methods. According to MP-SPR results, this study demonstrated that gum adsorbed on all surfaces and that adsorption is the most favorable at both acid pH and hydrophobic environments, i.e., when both the surface and the biopolymer are weakly hydrated and more prone to interfacial dehydration. These results reinforce our recent proposal of interfacial dehydration-induced structuring of biopolymers. Increasing the pH logically decreased the adsorption capacity, especially on a hydrophilic surface, enhancing the hydration rate of the layer. A hydrophilic surface is unfavorable to Acacia gum adsorption except if the surface presents a negative surface charge. In this case, interfacial charge dehydration was promoted by attractive electrostatic interactions between the surface and biopolymers. In the aggregate, the water percentage and the viscoelastic properties were closely related to the properties of the surface function: the negative charge and hydrophobicity significantly increased the hydration rate and viscoelastic properties with the pH, while the positive charge induced a rigid and more dehydrated layer.
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Affiliation(s)
| | - Michaël Nigen
- UMR IATE, Univ Montpellier, INRAE, Institut Agro, 34060 Montpellier, France
| | - Christian Sanchez
- UMR IATE, Univ Montpellier, INRAE, Institut Agro, 34060 Montpellier, France
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3
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Davantès A, Nigen M, Sanchez C, Renard D. Impact of Hydrophobic and Electrostatic Forces on the Adsorption of Acacia Gum on Oxide Surfaces Revealed by QCM-D. COLLOIDS AND INTERFACES 2023. [DOI: 10.3390/colloids7020026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
The adsorption of Acacia gum from two plant exudates, A. senegal and A. seyal, at the solid-liquid interface on oxide surfaces was studied using a quartz crystal microbalance with dissipation monitoring (QCM-D). The impact of the hydrophobic and electrostatic forces on the adsorption capacity was investigated by different surface, hydrophobicity, and charge properties, and by varying the ionic strength or the pH. The results highlight that hydrophobic forces have higher impacts than electrostatic forces on the Acacia gum adsorption on the oxide surface. The Acacia gum adsorption capacity is higher on hydrophobic surfaces compared to hydrophilic ones and presents a higher stability with negatively charged surfaces. The structural configuration and charge of Acacia gum in the first part of the adsorption process are important parameters. Acacia gum displays an extraordinary ability to adapt to surface properties through rearrangements, conformational changes, and/or dehydration processes in order to reach the steadiest state on the solid surface. Rheological analysis from QCM-D data shows that the A. senegal layers present a viscous behavior on the hydrophilic surface and a viscoelastic behavior on more hydrophobic ones. On the contrary, A. seyal layers show elastic behavior on all surfaces according to the Voigt model or a viscous behavior on the hydrophobic surface when considering the power-law model.
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Affiliation(s)
| | - Michaël Nigen
- UMR IATE, Université Montpellier, INRAE, Institut Agro, 34060 Montpellier, France
| | - Christian Sanchez
- UMR IATE, Université Montpellier, INRAE, Institut Agro, 34060 Montpellier, France
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Gao W, Han X, Sun D, Li Y, Liu X, Yang S, Zhou Z, Qi Y, Jiao J, Zhao J. Antibacterial properties of antimicrobial peptide HHC36 modified polyetheretherketone. Front Microbiol 2023; 14:1103956. [PMID: 36998411 PMCID: PMC10043374 DOI: 10.3389/fmicb.2023.1103956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/22/2023] [Indexed: 03/18/2023] Open
Abstract
IntroductionPolyetheretherketone (PEEK) is considered to be a new type of orthopedic implant material due to its mechanical properties and biocompatibility. It is becoming a replacement for titanium (Ti) due to its near-human-cortical transmission and modulus of elasticity. However, its clinical application is limited because of its biological inertia and susceptibility to bacterial infection during implantation. To solve this problem, there is an urgent need to improve the antibacterial properties of PEEK implants.MethodsIn this work, we fixed antimicrobial peptide HHC36 on the 3D porous structure of sulfonated PEEK (SPEEK) by a simple solvent evaporation method (HSPEEK), and carried out characterization tests. We evaluated the antibacterial properties and cytocompatibility of the samples in vitro. In addition, we evaluated the anti-infection property and biocompatibility of the samples in vivo by establishing a rat subcutaneous infection model.ResultsThe characterization test results showed that HHC36 was successfully fixed on the surface of SPEEK and released slowly for 10 days. The results of antibacterial experiments in vitro showed that HSPEEK could reduce the survival rate of free bacteria, inhibit the growth of bacteria around the sample, and inhibit the formation of biofilm on the sample surface. The cytocompatibility test in vitro showed that the sample had no significant effect on the proliferation and viability of L929 cells and had no hemolytic activity on rabbit erythrocytes. In vivo experiments, HSPEEK can significantly reduce the bacterial survival rate on the sample surface and the inflammatory reaction in the soft tissue around the sample.DiscussionWe successfully loaded HHC36 onto the surface of SPEEK through a simple solvent evaporation method. The sample has excellent antibacterial properties and good cell compatibility, which can significantly reduce the bacterial survival rate and inflammatory reaction in vivo. The above results indicated that we successfully improved the antibacterial property of PEEK by a simple modification strategy, making it a promising material for anti-infection orthopedic implants.
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Affiliation(s)
- Weijia Gao
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Xiao Han
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Duo Sun
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Yongli Li
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Xiaoli Liu
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Pediatric Dentistry, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Shihui Yang
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Prostheses, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Zhe Zhou
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Yuanzheng Qi
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Junjie Jiao
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Jinghui Zhao
- Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling, Department of Dental Implantology, Hospital of Stomatology, Jilin University, Changchun, Jilin, China
- *Correspondence: Jinghui Zhao,
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Rahimi E, Imani A, Lekka M, Andreatta F, Gonzalez-Garcia Y, Mol JMC, Asselin E, Fedrizzi L. Morphological and Surface Potential Characterization of Protein Nanobiofilm Formation on Magnesium Alloy Oxide: Their Role in Biodegradation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:10854-10866. [PMID: 35994730 PMCID: PMC9454254 DOI: 10.1021/acs.langmuir.2c01540] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/15/2022] [Indexed: 06/15/2023]
Abstract
The formation of a protein nanobiofilm on the surface of degradable biomaterials such as magnesium (Mg) and its alloys influences metal ion release, cell adhesion/spreading, and biocompatibility. During the early stage of human body implantation, competition and interaction between inorganic species and protein molecules result in a complex film containing Mg oxide and a protein layer. This film affects the electrochemical properties of the metal surface, the protein conformational arrangement, and the electronic properties of the protein/Mg oxide interface. In this study, we discuss the impact of various simulated body fluids, including sodium chloride (NaCl), phosphate-buffered saline (PBS), and Hanks' solutions on protein adsorption, electrochemical interactions, and electrical surface potential (ESP) distribution at the adsorbed protein/Mg oxide interface. After 10 min of immersion in NaCl, atomic force microscopy (AFM) and scanning Kelvin probe force microscopy (SKPFM) showed a higher surface roughness related to enhanced degradation and lower ESP distribution on a Mg-based alloy than those in other solutions. Furthermore, adding bovine serum albumin (BSA) to all solutions caused a decline in the total surface roughness and ESP magnitude on the Mg alloy surface, particularly in the NaCl electrolyte. Using SKPFM surface analysis, we detected a protein nanobiofilm (∼10-20 nm) with an aggregated and/or fibrillary morphology only on the Mg surface exposed in Hanks' and PBS solutions; these surfaces had a lower ESP value than the oxide layer.
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Affiliation(s)
- Ehsan Rahimi
- Polytechnic
Department of Engineering and Architecture, University of Udine, 33100 Udine, Italy
- Department
of Materials Science and Engineering, Delft
University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Amin Imani
- Department
of Materials Engineering, The University
of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Maria Lekka
- CIDETEC,
Basque Research and Technology Alliance (BRTA), Po. Miramón 196, 20014 Donostia-San Sebastián, Spain
| | - Francesco Andreatta
- Polytechnic
Department of Engineering and Architecture, University of Udine, 33100 Udine, Italy
| | - Yaiza Gonzalez-Garcia
- Department
of Materials Science and Engineering, Delft
University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Johannes M. C. Mol
- Department
of Materials Science and Engineering, Delft
University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Edouard Asselin
- Department
of Materials Engineering, The University
of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Lorenzo Fedrizzi
- Polytechnic
Department of Engineering and Architecture, University of Udine, 33100 Udine, Italy
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6
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Rahimi E, Offoiach R, Lekka M, Fedrizzi L. Electronic properties and surface potential evaluations at the protein nano-biofilm/oxide interface: Impact on corrosion and biodegradation. Colloids Surf B Biointerfaces 2022; 212:112346. [PMID: 35074638 DOI: 10.1016/j.colsurfb.2022.112346] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/15/2022] [Accepted: 01/17/2022] [Indexed: 11/16/2022]
Abstract
The formation of a protein nano-biofilm, which exhibits a special electronic behavior, on the surface of metals or oxide biomaterials considerably influences the crucial subsequent interactions, particularly the corrosion and biodegradation processes. This study discusses the impact of electrical surface potential (ESP) of a single or nano-biofilm of albumin protein on the electrochemical interactions and electronic property evolutions (e.g., charge carriers, space charge capacitance (SCC), and band bending) occurring on the surface oxide of CoCrMo implants. Scanning Kelvin probe force microscopy (SKPFM) results indicated that ESP or surface charge distribution on a single or nano-biofilm of the albumin protein is lower than that of a CoCrMo complex oxide layer, which hinders the charge transfer at the protein/electrolyte interface. Using a complementary approach, which involved performing Mott-Schottky analysis at the electrolyte/protein/oxide interface, it was revealed that the albumin protein significantly increases the SCC magnitude and number of n-type charge carrier owing to increased band bending at the SCC/protein interface; this facilitated the acceleration of metal ion release and metal-protein complex formation. The nanoscale SKPFM and electrochemical analyses performed in this study provide a better understanding of the role of protein molecules in corrosion/biodegradation of metallic biomaterials at the protein nano-biofilm/oxide interface.
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Affiliation(s)
- Ehsan Rahimi
- Polytechnic Department of Engineering and Architecture, University of Udine, 33100 Udine, Italy.
| | - Ruben Offoiach
- Polytechnic Department of Engineering and Architecture, University of Udine, 33100 Udine, Italy
| | - Maria Lekka
- CIDETEC, Basque Research and Technology Alliance (BRTA), Po. Miramón 196, 20014 DonostiaSan Sebastián, Spain.
| | - Lorenzo Fedrizzi
- Polytechnic Department of Engineering and Architecture, University of Udine, 33100 Udine, Italy
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7
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Davantès A, Nigen M, Sanchez C, Renard D. Adsorption Behavior of Arabinogalactan-Proteins (AGPs) from Acacia senegal Gum at a Solid-Liquid Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:10547-10559. [PMID: 34427446 DOI: 10.1021/acs.langmuir.1c01619] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Adsorption of five different hyperbranched arabinogalactan-protein (AGP) fractions from Acacia senegal gum was thoroughly studied at the solid-liquid interface using a quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR), and atomic force microscopy (AFM). The impact of the protein/sugar ratio, molecular weight, and aggregation state on the adsorption capacity was investigated by studying AGP fractions with different structural and biochemical features. Adsorption on a solid surface would be primarily driven by the protein moiety of the AGPs through hydrophobic forces and electrostatic interactions. Increasing ionic strength allows the decrease in electrostatic repulsions and, therefore, the formation of high-coverage films with aggregates on the surface. However, the maximum adsorption capacity was not reached by fractions with a higher protein content but by a fraction that contains an average protein quantity and presents a high content of high-molecular-weight AGPs. The results of this thorough study highlighted that the AGP surface adsorption process would depend not only on the protein moiety and high-molecular-weight AGP content but also on other parameters such as the structural accessibility of proteins, the molecular weight distribution, and the AGP flexibility, allowing structural rearrangements on the surface and spreading to form a viscoelastic film.
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Affiliation(s)
- Athénaïs Davantès
- UR BIA, INRAE Pays de la Loire, 3 impasse Yvette Cauchois, La Géraudière, CS 71627, F-44316 Nantes Cedex 3, France
| | - Michaël Nigen
- UMR IATE, UM-INRAE-CIRAD-Montpellier Supagro, 2 Place Viala, F-34060 Montpellier Cedex, France
| | - Christian Sanchez
- UMR IATE, UM-INRAE-CIRAD-Montpellier Supagro, 2 Place Viala, F-34060 Montpellier Cedex, France
| | - Denis Renard
- UR BIA, INRAE Pays de la Loire, 3 impasse Yvette Cauchois, La Géraudière, CS 71627, F-44316 Nantes Cedex 3, France
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Mieda S. Analysis of the Interaction between a Protein and Polymer Membranes Using Steered Molecular Dynamics Simulation to Interpret the Fouling Behavior. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20200173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Shunsuke Mieda
- Platform Laboratory for Science & Technology, Asahi Kasei Corporation, 2-1 Samejima, Fuji, Shizuoka 416-8501, Japan
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9
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Fies WA, First JT, Dugger JW, Doucet M, Browning JF, Webb LJ. Quantifying the Extent of Hydration of a Surface-Bound Peptide Using Neutron Reflectometry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:637-649. [PMID: 31846580 DOI: 10.1021/acs.langmuir.9b02559] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Establishing how water, or the absence of water, affects the structure, dynamics, and function of proteins in contact with inorganic surfaces is critical to developing successful protein immobilization strategies. In the present article, the quantity of water hydrating a monolayer of helical peptides covalently attached to self-assembled monolayers (SAMs) of alkyl thiols on Au was measured using neutron reflectometry (NR). The peptide sequence was composed of repeating LLKK units in which the leucines were aligned to face the SAM. When immersed in water, NR measured 2.7 ± 0.9 water molecules per thiol in the SAM layer and between 75 ± 13 and 111 ± 13 waters around each peptide. The quantity of water in the SAM was nearly twice that measured prior to peptide functionalization, suggesting that the peptide disrupted the structure of the SAM. To identify the location of water molecules around the peptide, we compared our NR data to previously published molecular dynamics simulations of the same peptide on a hydrophobic SAM in water, revealing that 49 ± 5 of 95 ± 8 total nearby water molecules were directly hydrogen-bound to the peptide. Finally, we show that immersing the peptide in water compressed its structure into the SAM surface. Together, these results demonstrate that there is sufficient water to fully hydrate a surface-bound peptide even at hydrophobic interfaces. Given the critical role that water plays in biomolecular structure and function, these results are expected to be informative for a broad array of applications involving proteins at the bio/abio interface.
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Affiliation(s)
- Whitney A Fies
- Department of Chemistry and Texas Materials Institute , The University of Texas at Austin , 2506 Speedway STOP A5300 , Austin , Texas 78712 , United States
| | - Jeremy T First
- Department of Chemistry and Texas Materials Institute , The University of Texas at Austin , 2506 Speedway STOP A5300 , Austin , Texas 78712 , United States
| | - Jason W Dugger
- Center for Nanophase Materials Sciences , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37830 , United States
| | - Mathieu Doucet
- Neutron Scattering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - James F Browning
- Neutron Scattering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Lauren J Webb
- Department of Chemistry and Texas Materials Institute , The University of Texas at Austin , 2506 Speedway STOP A5300 , Austin , Texas 78712 , United States
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10
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Protein film formation on cell culture surfaces investigated by quartz crystal microbalance with dissipation monitoring and atomic force microscopy. Colloids Surf B Biointerfaces 2019; 183:110447. [DOI: 10.1016/j.colsurfb.2019.110447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 08/15/2019] [Accepted: 08/18/2019] [Indexed: 12/16/2022]
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Rubio-Lara JA, Bergler F, Attwood SJ, Edwardson JM, Welland ME. Ultraflat Gold QCM Electrodes Fabricated with Pressure-Forming Template Stripping for Protein Studies at the Nanoscale. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8889-8895. [PMID: 30857390 DOI: 10.1021/acs.langmuir.8b03782] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Single-molecule imaging of proteins using atomic force microscopy (AFM) is crucially dependent on protein attachment to ultraflat substrates. The template-stripping (TS) technique, which can be used to create large areas of atomically flat gold, has been used to great effect for this purpose. However, this approach requires an epoxy, which can swell in solution, causing surface roughening and substantially increasing the thickness of any sample, preventing its use on acoustic resonators in liquid. Diffusion bonding techniques should circumvent this problem but cannot be used on samples containing patterned features with mismatched heights because of cracking and poor transfer. Here, we describe a new technique called pressure-forming TS (PTS), which permits an ultraflat (0.35 ± 0.05 nm root-mean-square roughness) layer of gold to be transferred to the surface of a patterned substrate at low temperature and pressure. We demonstrate this technique by modifying a quartz crystal microbalance (QCM) sensor to contain an ultraflat gold surface. Standard QCM chips have substantial roughness, preventing AFM imaging of proteins on the surface after measurement. With our approach, there is no need to run samples in parallel: the modified QCM chip is flat enough to permit high-contrast AFM imaging after adsorption studies have been conducted. The PTS-QCM chips are then used to demonstrate adsorption of bovine serum albumin in comparison to rough QCM chips. The ability to attach thin layers of ultraflat metals to surfaces of heterogeneous nature without epoxy will have many applications in diverse fields where there is a requirement to observe nanoscale phenomena with multiple techniques, including surface and interfacial science, optics, and biosensing.
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Affiliation(s)
- Juan A Rubio-Lara
- Nanoscience Centre , University of Cambridge , 11 JJ Thomson Avenue , Cambridge CB3 0FF , U.K
| | - Frederik Bergler
- Department of Pharmacology , University of Cambridge , Tennis Court Road , Cambridge CB2 1PD , U.K
| | - Simon J Attwood
- Nanoscience Centre , University of Cambridge , 11 JJ Thomson Avenue , Cambridge CB3 0FF , U.K
| | - J Michael Edwardson
- Department of Pharmacology , University of Cambridge , Tennis Court Road , Cambridge CB2 1PD , U.K
| | - Mark E Welland
- Nanoscience Centre , University of Cambridge , 11 JJ Thomson Avenue , Cambridge CB3 0FF , U.K
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Abstract
Hydrogenated nanocrystalline silicon, while being non-charged and non-polar, could be an ideal candidate for the non-covalent and orientation-controlled immobilization of biomolecules thanks to local electric fields around nanocrystals. To that effect, the adsorption of bovine serum albumin on substrates with different densities of nanocrystals, revealed by Raman spectroscopy and X-ray diffraction, was studied using infrared spectroscopy and atomic force microscopy. It was found that the protein–surface interactions followed different mechanisms depending on the nanostructure at the surface: hydrophobic on the non-crystalline part of the surface and electrostatic around the crystalline part. These electrostatic interactions were driven by the electric fields that arose at the junction between crystalline and amorphous structures. These electric fields were found to be strong enough to interact with the amide dipoles, thereby reorienting the adsorbed protein molecules on this part of the surface. Nevertheless, the adsorbed proteins were found to be denatured, which was due to the surface chemistry, and not affected by the nanostructure.
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