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Stackhouse CI, Pierson KN, Labrecque CL, Mawson C, Berg J, Fuglestad B, Nucci NV. Characterization of 10MAG/LDAO reverse micelles: Understanding versatility for protein encapsulation. Biophys Chem 2024; 311:107269. [PMID: 38815545 PMCID: PMC11225088 DOI: 10.1016/j.bpc.2024.107269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/01/2024]
Abstract
Reverse micelles (RMs) are spontaneously organizing nanobubbles composed of an organic solvent, surfactants, and an aqueous phase that can encapsulate biological macromolecules for various biophysical studies. Unlike other RM systems, the 1-decanoyl-rac-glycerol (10MAG) and lauryldimethylamine-N-oxide (LDAO) surfactant system has proven to house proteins with higher stability than other RM mixtures with little sensitivity to the water loading (W0, defined by the ratio of water to surfactant). We investigated this unique property by encapsulating three model proteins - cytochrome c, myoglobin, and flavodoxin - in 10MAG/LDAO RMs and applying a variety of experimental methods to characterize this system's behavior. We found that this surfactant system differs greatly from the traditional, spherical, monodisperse RM population model. 10MAG/LDAO RMs were discovered to be oblate ellipsoids at all conditions, and as W0 was increased, surfactants redistributed to form a greater number of increasingly spherical ellipsoidal particles with pools of more bulk-like water. Proteins distinctively influence the thermodynamics of the mixture, encapsulating at their optimal RM size and driving protein-free RM sizes to scale accordingly. These findings inform the future development of similarly malleable encapsulation systems and build a foundation for application of 10MAG/LDAO RMs to analyze biological and chemical processes under nanoscale confinement.
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Affiliation(s)
- Crystal I Stackhouse
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
| | - Kali N Pierson
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
| | - Courtney L Labrecque
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
| | - Cara Mawson
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
| | - Joshua Berg
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States
| | - Brian Fuglestad
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States; Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219, United States.
| | - Nathaniel V Nucci
- Department of Physics and Astronomy, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States; Department of Biomedical and Biological Sciences, Rowan University, 201 Mullica Hill Rd, Glassboro, NJ 08028, United States.
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2
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Hou Y, Ling Y, Wang Y, Wang M, Chen Y, Li X, Hou X. Learning from the Brain: Bioinspired Nanofluidics. J Phys Chem Lett 2023; 14:2891-2900. [PMID: 36927003 DOI: 10.1021/acs.jpclett.2c03930] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The human brain completes intelligent behaviors such as the generation, transmission, and storage of neural signals by regulating the ionic conductivity of ion channels in neuron cells, which provides new inspiration for the development of ion-based brain-like intelligence. Against the backdrop of the gradual maturity of neuroscience, computer science, and micronano materials science, bioinspired nanofluidic iontronics, as an emerging interdisciplinary subject that focuses on the regulation of ionic conductivity of nanofluidic systems to realize brain-like functionalities, has attracted the attention of many researchers. This Perspective provides brief background information and the state-of-the-art progress of nanofluidic intelligent systems. Two main categories are included: nanofluidic transistors and nanofluidic memristors. The prospects of nanofluidic iontronics' interdisciplinary progress in future artificial intelligence fields such as neuromorphic computing or brain-computer interfaces are discussed. This Perspective aims to give readers a clear understanding of the concepts and prospects of this emerging interdisciplinary field.
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Affiliation(s)
- Yaqi Hou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- The Institute of Flexible Electronics (IFE, Future Technologies), Xiamen University, Xiamen 361005, China
| | - Yixin Ling
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yanqiong Wang
- The Institute of Flexible Electronics (IFE, Future Technologies), Xiamen University, Xiamen 361005, China
| | - Miao Wang
- Institute of Artificial Intelligence, Xiamen University, Xiamen 361005, China
- College of Materials, Xiamen University, Xiamen 361005, China
| | - Yeyun Chen
- Institute of Artificial Intelligence, Xiamen University, Xiamen 361005, China
| | - Xipeng Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- Binzhou Institute of Technology, Binzhou, 256600, China
| | - Xu Hou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- Department of Physics, Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials Research, Jiujiang Research Institute, College of Physical Science and Technology, Xiamen University, Xiamen 361005, China
- Institute of Artificial Intelligence, Xiamen University, Xiamen 361005, China
- Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361102, China
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3
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Cho SS, Green AT, Hyeon C, Thirumalai D. TMAO Destabilizes RNA Secondary Structure via Direct Hydrogen Bond Interactions. J Phys Chem B 2023; 127:438-445. [PMID: 36602908 DOI: 10.1021/acs.jpcb.2c05434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Trimethylamine N-oxide (TMAO) is an osmolyte that accumulates in cells in response to osmotic stress. TMAO stabilizes proteins by the entropic stabilization mechanism, which pictures TMAO as a nanocrowder that predominantly destabilizes the unfolded state. However, the mechanism of action of TMAO on RNA is much less understood. Here, we use all-atom molecular dynamics simulations to investigate how TMAO interacts with a 12-nt RNA hairpin with a high melting temperature, and an 8-nt RNA hairpin, which has a relatively fluid native basin in the absence of TMAO. The use of the two hairpins with different free energy of stabilization allows us to probe the origin of the destabilization effect of TMAO on RNA molecules without the possibility of forming tertiary interactions. We generated multiple trajectories using all-atom molecular dynamics (MD) simulations in explicit water by employing AMBER and CHARMM force fields, both in the absence and presence of TMAO. We observed qualitatively similar RNA-TMAO interaction profiles from the simulations using the two force fields. TMAO hydrogen bond interactions are largely depleted around the paired RNA bases and ribose sugars. In contrast, we show that the oxygen atom in TMAO, the hydrogen bond acceptor, preferentially interacts with the hydrogen bond donors in the solvent exposed bases, such as those in the stem-loop and the destabilized base stacks in the unfolded state, especially in the marginally stable 8-nt RNA hairpin. The predicted destabilization mechanism through TMAO-RNA hydrogen bond interactions could be tested using two-dimensional IR spectroscopy. Since TMAO does not significantly interact with the hydroxyl group of the ribose sugars, we predict that similar results must also hold for DNA.
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Affiliation(s)
- Samuel S Cho
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, United States.,Department of Computer Science, Wake Forest University, Winston-Salem, North Carolina 27109, United States
| | - Adam T Green
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, United States
| | - Changbong Hyeon
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - D Thirumalai
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.,Department of Physics, University of Texas at Austin, Austin, Texas 78712, United States
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4
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Mondarte EAQ, Zamarripa EMM, Chang R, Wang F, Song S, Tahara H, Hayashi T. Interphase Protein Layers Formed on Self-Assembled Monolayers in Crowded Biological Environments: Analysis by Surface Force and Quartz Crystal Microbalance Measurements. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:1324-1333. [PMID: 35029393 DOI: 10.1021/acs.langmuir.1c02312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We investigated a viscous protein layer formed on self-assembled monolayers (SAMs) in crowded biological environments. The results were obtained through force spectroscopic measurements using colloidal probes and substantiated by exhaustive analysis using a quartz crystal microbalance with an energy dissipation technique. A hydrophobic SAM of n-octanethiol (C8 SAM) in bovine serum albumin (BSA) solution is buried under an adlayer of denatured BSA molecules and an additional viscous interphase layer that is five times more viscous than the bulk solution. C8 SAMs in fetal bovine serum induced a formation of a thicker adsorbed protein layer but with no observable viscous interphase layer. These findings show that a fouling surface is essentially inaccessible to any approaching molecules and thus has a new biological and physical identity arising from its surrounding protein layers. In contrast, the SAMs composed of sulfobetaine-terminated alkanethiol proved to be sufficiently protein-resistant and bio-inert even under crowded conditions due to a protective barrier of its interfacial water, which has implications in the accurate targeting of artificial particles for drug delivery and similar applications by screening any non-specific interactions. Finally, our strategies provide a platform for the straightforward yet effectual in vitro characterization of diverse types of surfaces in the context of targeted interactions in crowded biological environments.
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Affiliation(s)
- Evan Angelo Quimada Mondarte
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Elisa Margarita Mendoza Zamarripa
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Ryongsok Chang
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Fan Wang
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Subin Song
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Hiroyuki Tahara
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
| | - Tomohiro Hayashi
- Tokyo Institute of Technology, Department of Materials Science and Engineering, School of Materials and Chemical Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan
- The Institute for Solid State Physics, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
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5
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Sung HL, Sengupta A, Nesbitt D. Smaller molecules crowd better: Crowder size dependence revealed by single-molecule FRET studies and depletion force modeling analysis. J Chem Phys 2021; 154:155101. [PMID: 33887926 DOI: 10.1063/5.0045492] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The cell is an extremely crowded environment, which is known to have a profound impact on the thermodynamics, functionality, and conformational stability of biomolecules. Speculations from recent theoretical molecular dynamics studies suggest an intriguing size dependence to such purely entropic crowding effects, whereby small molecular weight crowders under constant enthalpy conditions are more effective than larger crowders on a per volume basis. If experimentally confirmed, this would be profoundly significant, as the cellular cytoplasm is also quite concentrated in smaller molecular weight solutes such as inorganic ions, amino acids, and various metabolites. The challenge is to perform such studies isolating entropic effects under isoenthalpic conditions. In this work, we first present results from single-molecule FRET spectroscopy (smFRET) on the molecular size-dependent crowding stabilization of a simple RNA tertiary motif (the GAAA tetraloop-tetraloop receptor), indeed providing evidence in support of the surprising notion in the crowding literature that "smaller is better." Specifically, systematic smFRET studies as a function of crowder solute size reveal that smaller molecules both significantly increase the RNA tertiary folding rate and, yet, simultaneously decrease the unfolding rate, predicting strongly size-dependent stabilization of RNA tertiary structures under crowded cellular conditions. The size dependence of these effects has been explored via systematic variation of crowder size over a broad range of molecular weights (90-3000 amu). Furthermore, corresponding temperature dependent studies indicate the systematic changes in the folding equilibrium to be predominantly entropic in origin, i.e., consistent with a fundamental picture of entropic molecular crowding without additional enthalpic interactions. Most importantly, all trends in the single-molecule crowding data can be quantitatively recapitulated by a simple analytic depletion force model, whereby excluded volume interactions represent the major thermodynamic driving force toward folding. Our study, thus, not only provides experimental evidence and theoretical support for small molecule crowding but also predicts further enhancement of crowding effects for even smaller molecules on a per volume basis.
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Affiliation(s)
- Hsuan-Lei Sung
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA
| | - Abhigyan Sengupta
- Biophysics Department, Technical University of Munich, Garching, Germany
| | - David Nesbitt
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, USA
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6
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Zeugolis DI. Bioinspired in vitro microenvironments to control cell fate: focus on macromolecular crowding. Am J Physiol Cell Physiol 2021; 320:C842-C849. [PMID: 33656930 DOI: 10.1152/ajpcell.00380.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The development of therapeutic regenerative medicine and accurate drug discovery cell-based products requires effective, with respect to obtaining sufficient numbers of viable, proliferative, and functional cell populations, cell expansion ex vivo. Unfortunately, traditional cell culture systems fail to recapitulate the multifaceted tissue milieu in vitro, resulting in cell phenotypic drift, loss of functionality, senescence, and apoptosis. Substrate-, environment-, and media-induced approaches are under intense investigation as a means to maintain cell phenotype and function while in culture. In this context, herein, the potential of macromolecular crowding, a biophysical phenomenon with considerable biological consequences, is discussed.
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Affiliation(s)
- Dimitrios I Zeugolis
- Regenerative, Modular, and Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway, Galway, Ireland.,Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway, Galway, Ireland.,Faculty of Biomedical Sciences, Regenerative, Modular, and Developmental Engineering Laboratory (REMODEL), Università della Svizzera Italiana, Lugano, Switzerland.,Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland
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7
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Nayar D. Small crowder interactions can drive hydrophobic polymer collapse as well as unfolding. Phys Chem Chem Phys 2020; 22:18091-18101. [PMID: 32760995 DOI: 10.1039/d0cp02402c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biomolecules evolve and function in the intracellular crowded environment that is densely packed with macromolecules. Yet, a microscopic understanding of the effects of such an environment on the conformational preferences of biomolecules remains elusive. While prior investigations have attributed crowding effects mainly to the excluded volume (size) effects of the crowders, very little is known about the effects exerted due to their chemical interactions. In this study, crowding effects of tri-alanine peptides on the collapse equilibria of generic hydrophobic polymer are investigated using molecular dynamics simulations. The role of weak, non-specific, attractive polymer-crowder interactions in modulating the polymer collapse equilibria is examined. The results highlight that crowding effects can lead to polymer compaction as well as unfolding depending on the strength of polymer-crowder interaction energy. Strongly interacting crowders weaken hydrophobic collapse (or unfold the polymer) at high volume fractions and induce polymer collapse only under dilute conditions. Weakly interacting crowders induce polymer collapse at all crowder concentrations. Interestingly, the thermodynamic driving forces for polymer collapse are remarkably different in the two cases. Strongly and weakly interacting crowders induce collapse by preferential adsorption and preferential depletion respectively. The findings provide new insights into the possible effects of interplay of intermolecular interactions in a crowded environment. The results have implications in understanding the impact of crowding in altering free energy landscapes of proteins.
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Affiliation(s)
- Divya Nayar
- Centre for Computational and Data Sciences, Indian Institute of Technology Kharagpur, West Bengal 721302, India.
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8
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Warning LA, Zhang Q, Baiyasi R, Landes CF, Link S. Nanoscale Surface-Induced Unfolding of Single Fibronectin Is Restricted by Serum Albumin Crowding. J Phys Chem Lett 2020; 11:1170-1177. [PMID: 31967479 DOI: 10.1021/acs.jpclett.9b03446] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Understanding nanoscale protein conformational changes at solid-liquid interfaces is critical for predicting how proteins will impact the performance of biomaterials in vivo. Crowding is an important contributor to conformational stability. Here we apply single-molecule high resolution imaging with photobleaching to directly measure dye-conjugated fibronectin's unfolding in varying conditions of crowding with human serum albumin on aminosilanized glass. Using this approach, we identify serum albumin's crowding mechanism. We find that fibronectin achieves larger degrees of unfolding when not crowded by coadsorbed serum albumin. Serum albumin does not as effectively constrict fibronectin's conformation if it is sequentially, rather than simultaneously, introduced, suggesting that serum albumin's crowding mechanism is dependent on its ability to sterically block fibronectin's unfolding during the process of adsorption. Because fibronectin's conformation is dependent on interfacial macromolecular crowding under in vitro conditions, it is important to consider the role of in vivo crowding on protein activity.
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9
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Deshwal A, Chitra H, Maity M, Pal SK, Maiti S. Sucrose-mediated heat-stiffening microemulsion-based gel for enzyme entrapment and catalysis. Chem Commun (Camb) 2020; 56:10698-10701. [DOI: 10.1039/d0cc04294c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Formation of a thermo-stiffening microemulsion-based-gel showing the nanoconfinement effect of carbohydrates as an efficient batch bioreactor for entrapped enzymes has been reported.
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Affiliation(s)
- Akshi Deshwal
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Knowledge City
- India
| | - Himanshu Chitra
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Knowledge City
- India
| | - Madhusudan Maity
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Knowledge City
- India
| | - Santanu Kumar Pal
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Knowledge City
- India
| | - Subhabrata Maiti
- Department of Chemical Sciences
- Indian Institute of Science Education and Research (IISER) Mohali
- Knowledge City
- India
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10
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Downs AM, McCallum C, Pennathur S. Confinement effects on DNA hybridization in electrokinetic micro- and nanofluidic systems. Electrophoresis 2019; 40:792-798. [PMID: 30597594 DOI: 10.1002/elps.201800356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 11/29/2018] [Accepted: 12/02/2018] [Indexed: 11/09/2022]
Abstract
Spatial confinement, within cells or micro- and nanofabricated devices, impacts the conformation and binding kinetics of biomolecules. Understanding the role of spatial confinement on molecular behavior is important for comprehending diverse biological phenomena, as well as for designing biosensors. Specifically, the behavior of molecular binding under an applied electric field is of importance in the development of electrokinetic biosensors. Here, we investigate whether confinement of DNA oligomers in capillary electrophoresis impacts the binding kinetics of the DNA. To infer the role of confinement on hybridization dynamics, we perform capillary electrophoresis measurements on DNA oligomers within micro- and nanochannels, then apply first-order reaction dynamics theory to extract kinetic parameters from electropherogram data. We find that the apparent dissociation constants at the nanoscale (i.e., within a 100 nm channel) are lower than at the microscale (i.e., within a 1 μm channel), indicating stronger binding with increased confinement. This confirms, for the first time, that confinement-based enhancement of DNA hybridization persists under application of an electric field.
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Affiliation(s)
- Alex M Downs
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - Christopher McCallum
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
| | - Sumita Pennathur
- Department of Mechanical Engineering, University of California, Santa Barbara, CA, USA
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11
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Ding B, Yang L, Mukherjee D, Chen J, Gao Y, Gai F. Microscopic Insight into the Protein Denaturation Action of Urea and Its Methyl Derivatives. J Phys Chem Lett 2018; 9:2933-2940. [PMID: 29767523 DOI: 10.1021/acs.jpclett.8b00960] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We employ site-specific, linear and nonlinear infrared spectroscopic techniques as well as fluorescence spectroscopy and molecular dynamics simulations to investigate the binding interactions of urea and three of its derivatives, methylurea, 1,3-dimethylurea, and tetramethylurea, with protein aromatic and polar side chains. We find that (1) urea methylation leads to preferential interactions between the cosolvent molecules and aromatic side chains with an affinity that increases with the number of methyl groups; (2) interactions with tetramethylurea cause significant dehydration of aromatic side chains and the effect is most pronounced for tryptophan; and (3) while neither urea nor tetramethylurea shows preferential accumulation around a polar side chain, the number of hydrogen-bond donors around this side chain is significantly decreased in the presence of tetramethylurea. Taken together, our findings suggest that these urea derivatives, especially tetramethylurea, can effectively disrupt hydrophobic interactions in proteins. Additionally, tetramethylurea can promote intramolecular hydrogen-bond formation and hence induce α-helix folding in peptides, as observed.
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Affiliation(s)
| | - Lijiang Yang
- College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
| | | | | | - Yiqin Gao
- College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , China
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12
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Borgohain G, Paul S. Atomistic level understanding of the stabilization of protein Trp cage in denaturing and mixed osmolyte solutions. COMPUT THEOR CHEM 2018. [DOI: 10.1016/j.comptc.2018.03.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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13
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Alvarado YJ, Ferrebuz A, Paz JL, Rodríguez-Lugo P, Restrepo J, Romero F, Fernández-Acuña J, Williams YO, Toro-Mendoza J. Surface Behavior of BSA/Water/Carbohydrate Systems from Molecular Polarizability Measurements. J Phys Chem B 2018; 122:4231-4238. [PMID: 29582658 DOI: 10.1021/acs.jpcb.7b11998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effect of the presence of glucose and sucrose on the nonintrinsic contribution to partial molar volume ⟨Θ⟩ni of bovine serum albumin (BSA) is determined by means of static and dynamic electronic polarizability measurements. For that aim, a combined strategy based on high-resolution refractometry, high exactitude densitometry, and synchronous fluorescence spectroscopy is applied. Both static and dynamic mean electronic molecular polarizability values are found to be sensitive to the presence of glucose. In the case of sucrose, the polarizability of BSA is not appreciably affected. In fact, our results revealed that the electronic changes observed occurred without a modification of the native conformation of BSA. On the contrary, a nonmonotonous behavior with the concentration is observed in presence of glucose. These results advocate the influence of the electronic polarization on the repulsive and attractive protein-carbohydrate interactions. An analysis using the scaled particle theory indicates that the accumulation of glucose on the protein surface promotes dehydration. Inversely, hydration and preferential exclusion occur in the vicinity of the protein surface for sucrose-enriched systems.
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Affiliation(s)
| | | | - Jose Luis Paz
- Departamento de Física , Escuela Politécnica Nacional , Ladron de Guevara , Quito 170517 , Ecuador
| | - Patricia Rodríguez-Lugo
- Laboratorio de Electrónica Molecular, Facultad Experimental de Ciencias, Departamento de Química , Universidad del Zulia , Maracaibo 4001 , Venezuela
| | | | - Freddy Romero
- Center for Translational Medicine and Korman Lung Center , Thomas Jefferson University , Philadelphia , Pennsylvania 19107 , United States
| | - Jaqueline Fernández-Acuña
- Centro de Estudios Interdisciplinarios de la Física , Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas 1020A , Venezuela
| | - Yhan O'Neil Williams
- Centro de Estudios Interdisciplinarios de la Física , Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas 1020A , Venezuela
| | - Jhoan Toro-Mendoza
- Centro de Estudios Interdisciplinarios de la Física , Instituto Venezolano de Investigaciones Científicas (IVIC) , Caracas 1020A , Venezuela
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14
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Abaskharon RM, Gai F. Meandering Down the Energy Landscape of Protein Folding: Are We There Yet? Biophys J 2017; 110:1924-32. [PMID: 27166801 DOI: 10.1016/j.bpj.2016.03.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 12/11/2022] Open
Abstract
As judged by a single publication metric, the activity in the protein folding field has been declining over the past 5 years, after enjoying a decade-long growth. Does this development indicate that the field is sunsetting or is this decline only temporary? Upon surveying a small territory of its landscape, we find that the protein folding field is still quite active and many important findings have emerged from recent experimental studies. However, it is also clear that only continued development of new techniques and methods, especially those enabling dissection of the fine details and features of the protein folding energy landscape, will fuel this old field to move forward.
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Affiliation(s)
- Rachel M Abaskharon
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania; The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania.
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15
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Nirmalraj P, Daly R, Martin N, Thompson D. Motion of Fullerenes around Topological Defects on Metals: Implications for the Progress of Molecular Scale Devices. ACS APPLIED MATERIALS & INTERFACES 2017; 9:7897-7902. [PMID: 28233982 DOI: 10.1021/acsami.7b00408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Research on motion of molecules in the presence of thermal noise is central for progress in two-terminal molecular scale electronic devices. However, it is still unclear what influence imperfections in bottom metal electrode surface can have on molecular motion. Here, we report a two-layer crowding study, detailing the early stages of surface motion of fullerene molecules on Au(111) with nanoscale pores in a n-tetradecane chemical environment. The motion of the fullerenes is directed by crowding of the underlying n-tetradecane molecules around the pore fringes at the liquid-solid interface. We observe in real-space the growth of molecular populations around different pore geometries. Supported by atomic-scale modeling, our findings extend the established picture of molecular crowding by revealing that trapped solvent molecules serve as prime nucleation sites at nanopore fringes.
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Affiliation(s)
- Peter Nirmalraj
- IBM Research-Zurich , Säumerstrasse 4, CH- 8803 Rüschlikon, Switzerland
| | - Ronan Daly
- Department of Engineering, University of Cambridge , 17 Charles Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Nazario Martin
- Departmento de Quimica Organica, Facultad de Quimica, Universidad Complutense de Madrid , E-28040 Madrid, Spain
| | - Damien Thompson
- Department of Physics, Bernal Institute, University of Limerick , Limerick V94 T9PX, Ireland
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16
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Do guanidinium and tetrapropylammonium ions specifically interact with aromatic amino acid side chains? Proc Natl Acad Sci U S A 2017; 114:1003-1008. [PMID: 28096375 DOI: 10.1073/pnas.1618071114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Many ions are known to affect the activity, stability, and structural integrity of proteins. Although this effect can be generally attributed to ion-induced changes in forces that govern protein folding, delineating the underlying mechanism of action still remains challenging because it requires assessment of all relevant interactions, such as ion-protein, ion-water, and ion-ion interactions. Herein, we use two unnatural aromatic amino acids and several spectroscopic techniques to examine whether guanidinium chloride, one of the most commonly used protein denaturants, and tetrapropylammonium chloride can specifically interact with aromatic side chains. Our results show that tetrapropylammonium, but not guanidinium, can preferentially accumulate around aromatic residues and that tetrapropylammonium undergoes a transition at ∼1.3 M to form aggregates. We find that similar to ionic micelles, on one hand, such aggregates can disrupt native hydrophobic interactions, and on the other hand, they can promote α-helix formation in certain peptides.
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17
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Muttathukattil AN, Reddy G. Osmolyte Effects on the Growth of Amyloid Fibrils. J Phys Chem B 2016; 120:10979-10989. [DOI: 10.1021/acs.jpcb.6b09215] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Aswathy N. Muttathukattil
- Solid State and Structural
Chemistry Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Govardhan Reddy
- Solid State and Structural
Chemistry Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
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18
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Babayekhorasani F, Dunstan DE, Krishnamoorti R, Conrad JC. Nanoparticle diffusion in crowded and confined media. SOFT MATTER 2016; 12:8407-8416. [PMID: 27714348 DOI: 10.1039/c6sm01543c] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We identify distinct mechanisms controlling slowing of nanoparticle diffusion through complex media featuring both rigid geometrical confinement and soft mobile crowders. Towards this end, we use confocal microscopy and single particle tracking to probe the diffusion of 400 nm nanoparticles suspended in Newtonian water, in a Newtonian glycerol/water mixture, or in a non-Newtonian polymer solution through a model porous medium, a packed bed of microscale glass beads. The mobility of nanoparticles, as quantified by the long-time diffusion coefficient extracted from the particle mean-squared displacement, slows as the average pore size of the packed bed media decreases for both Newtonian and non-Newtonian solutions. The distribution of particle displacements is non-Gaussian, consistent with the spatial heterogeneity of the geometrical confinement imposed by the packed bed. The slowing of nanoparticle mobility in all solutions follows the predictions of models that describe hydrodynamic interactions with the packed bed. In non-Newtonian solutions, depletion interactions due to the polymers near the glass beads result in temporary adsorption of particles onto the bead surface, as indicated by a stretched-exponential distribution of residence times. Our results therefore suggest that the confined diffusive dynamics of nanoparticles in polymer solutions is controlled by two competing mechanisms: hydrodynamic interactions between particles and spatial obstacles, which dictate the long-time slowing of diffusion, and depletion interactions between particles and confining walls due to the macromolecules, which control transient adsorption and hence alter the statistics of the short-time motion.
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Affiliation(s)
| | - Dave E Dunstan
- Chemical and Biomolecular Engineering, University of Melbourne, 3010, Australia
| | - Ramanan Krishnamoorti
- Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA. and Department of Chemistry, University of Houston, Houston, Texas 77204, USA
| | - Jacinta C Conrad
- Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, USA.
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19
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Ferreira LA, Breydo L, Reichardt C, Uversky VN, Zaslavsky BY. Effects of osmolytes on solvent features of water in aqueous solutions. J Biomol Struct Dyn 2016; 35:1055-1068. [DOI: 10.1080/07391102.2016.1170633] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Luisa A. Ferreira
- Cleveland Diagnostics , 3615 Superior Ave., Suite 4407B, Cleveland, OH 44114, USA
| | - Leonid Breydo
- Department of Molecular Medicine and Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida , Tampa, FL 33612, USA
| | | | - Vladimir N. Uversky
- Department of Molecular Medicine and Byrd Alzheimer’s Research Institute, Morsani College of Medicine, University of South Florida , Tampa, FL 33612, USA
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences , St. Petersburg, Russia
| | - Boris Y. Zaslavsky
- Cleveland Diagnostics , 3615 Superior Ave., Suite 4407B, Cleveland, OH 44114, USA
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20
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Zhang W, Markiewicz BN, Doerksen RS, Smith AB, Gai F. C≡N stretching vibration of 5-cyanotryptophan as an infrared probe of protein local environment: what determines its frequency? Phys Chem Chem Phys 2016; 18:7027-34. [PMID: 26343769 PMCID: PMC4775302 DOI: 10.1039/c5cp04413h] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recently it has been suggested that the C≡N stretching vibration of a tryptophan analog, 5-cyanotryptophan, could be used as an infrared probe of the local environment, especially the hydration status, of tryptophan residues in proteins. However, the factors that influence the frequency of this vibrational mode are not understood. To determine these factors, herein we carried out linear and nonlinear infrared measurements on the C≡N stretching vibration of the sidechain of 5-cyanotryptophan, 3-methyl-5-cyanoindole, in a series of protic and aprotic solvents. We found that while the C≡N stretching frequencies obtained in these solvents do not correlate well with any individual Kamlet-Taft solvent parameter, i.e., π* (polarizability), β (hydrogen bond accepting ability), and α (hydrogen bond donating ability), they do however, collapse on a straight line when plotted against σ = π* + β - α. This linear relationship provides a firm indication that both specific interactions, i.e., hydrogen-bonding interactions with the C≡N (through α) and indole N-H (through β) groups, and non-specific interactions with the molecule (through π*) work together to determine the C≡N stretching frequency, thus laying a quantitative framework for applying 5-cyanotryptophan to investigate the microscopic environment of proteins in a site-specific manner. Furthermore, two-dimensional and pump-probe infrared measurements revealed that a significant portion (∼31%) of the ground state bleach signal has a decay time constant of ∼12.3 ps, due to an additional vibrational relaxation channel, making it possible to use 5-cyanotryptophan to probe dynamics occurring on a timescale on the order of tens of picoseconds.
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Affiliation(s)
- Wenkai Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA. and The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Rosalie S Doerksen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA. and The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
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21
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Zhang H, Lv Y, Tan T, van der Spoel D. Atomistic Simulation of Protein Encapsulation in Metal–Organic Frameworks. J Phys Chem B 2016; 120:477-84. [DOI: 10.1021/acs.jpcb.5b10437] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haiyang Zhang
- Beijing
Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Box 53, 100029 Beijing, China
- Department
of Biological Science and Engineering, School of Chemistry and Biological
Engineering, University of Science and Technology Beijing, 100083 Beijing, China
| | - Yongqin Lv
- Beijing
Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Box 53, 100029 Beijing, China
| | - Tianwei Tan
- Beijing
Key Lab of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Box 53, 100029 Beijing, China
| | - David van der Spoel
- Uppsala
Center for Computational Chemistry, Science for Life Laboratory, Department
of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box
596, SE-75124 Uppsala, Sweden
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22
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Biala K, Sedova A, Flechsig GU. Sequence and Temperature Influence on Kinetics of DNA Strand Displacement at Gold Electrode Surfaces. ACS APPLIED MATERIALS & INTERFACES 2015; 7:19948-19959. [PMID: 26302819 DOI: 10.1021/acsami.5b04435] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Understanding complex contributions of surface environment to tethered nucleic acid sensing experiments has proven challenging, yet it is important because it is essential for interpretation and calibration of indispensable methods, such as microarrays. We investigate the effects of DNA sequence and solution temperature gradients on the kinetics of strand displacement at heated gold wire electrodes, and at gold disc electrodes in a heated solution. Addition of a terminal double mismatch (toehold) provides a reduction in strand displacement energy barriers sufficient to probe the secondary mechanisms involved in the hybridization process. In four different DNA capture probe sequences (relevant for the identification of genetically modified maize MON810), all but one revealed a high activation energy up to 200 kJ/mol during hybridization, that we attribute to displacement of protective strands by capture probes. Protective strands contain 4 to 5 mismatches to ease their displacement by the surface-confined probes at the gold electrodes. A low activation energy (30 kJ/mol) was observed for the sequence whose protective strand contained a toehold and one central mismatch, its kinetic curves displayed significantly different shapes, and we observed a reduced maximum signal intensity as compared to other sequences. These findings point to potential sequence-related contributions to oligonucleotide diffusion influencing kinetics. Additionally, for all sequences studied with heated wire electrodes, we observed a 23 K lower optimal hybridization temperature in comparison with disc electrodes in heated solution, and greatly reduced voltammetric signals after taking into account electrode surface area. We propose that thermodiffusion due to temperature gradients may influence both hybridization and strand displacement kinetics at heated microelectrodes, an explanation supported by computational fluid dynamics. DNA assays with surface-confined capture probes and temperature gradients should not neglect potential influences of thermodiffusion as well as sequence-related effects. Furthermore, studies attempting to characterize surface-tethered environments should consider thermodiffusion if temperature gradients are involved.
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Affiliation(s)
- Katarzyna Biala
- Department of Chemistry, University at Albany, SUNY , 1400 Washington Avenue, Albany, New York 12222, United States
- Department of Chemistry, University of Rostock , A.-Einstein-Str. 3a, D-18059 Rostock, Germany
| | - Ada Sedova
- Department of Chemistry, University at Albany, SUNY , 1400 Washington Avenue, Albany, New York 12222, United States
| | - Gerd-Uwe Flechsig
- Department of Chemistry, University at Albany, SUNY , 1400 Washington Avenue, Albany, New York 12222, United States
- Department of Chemistry, University of Rostock , A.-Einstein-Str. 3a, D-18059 Rostock, Germany
- Gensoric GmbH, Schillingallee 68, D-18057 Rostock, Germany
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