1
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Hirschmann F, Lopez H, Roosen-Runge F, Seydel T, Schreiber F, Oettel M. Effects of flexibility in coarse-grained models for bovine serum albumin and immunoglobulin G. J Chem Phys 2023; 158:084112. [PMID: 36859072 DOI: 10.1063/5.0132493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
We construct a coarse-grained, structure-based, low-resolution, 6-bead flexible model of bovine serum albumin (BSA, PDB: 4F5S), which is a popular example of a globular protein in biophysical research. The model is obtained via direct Boltzmann inversion using all-atom simulations of a single molecule, and its particular form is selected from a large pool of 6-bead coarse-grained models using two suitable metrics that quantify the agreement in the distribution of collective coordinates between all-atom and coarse-grained Brownian dynamics simulations of solutions in the dilute limit. For immunoglobulin G (IgG), a similar structure-based 12-bead model has been introduced in the literature [Chaudhri et al., J. Phys. Chem. B 116, 8045 (2012)] and is employed here to compare findings for the compact BSA molecule and the more anisotropic IgG molecule. We define several modified coarse-grained models of BSA and IgG, which differ in their internal constraints and thus account for a variation of flexibility. We study denser solutions of the coarse-grained models with purely repulsive molecules (achievable by suitable salt conditions) and address the effect of packing and flexibility on dynamic and static behavior. Translational and rotational self-diffusivity is enhanced for more elastic models. Finally, we discuss a number of effective sphere sizes for the BSA molecule, which can be defined from its static and dynamic properties. Here, it is found that the effective sphere diameters lie between 4.9 and 6.1 nm, corresponding to a relative spread of about ±10% around a mean of 5.5 nm.
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Affiliation(s)
- Frank Hirschmann
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Hender Lopez
- School of Physics, Clinical and Optometric Sciences, Technological University Dublin, Grangegorman D07 ADY7, Ireland
| | - Felix Roosen-Runge
- Department of Biomedical Sciences and Biofilms-Research Center for Biointerfaces (BRCB), Malmö University, 20506 Malmö, Sweden
| | - Tilo Seydel
- Institut Max von Laue-Paul Langevin, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Frank Schreiber
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
| | - Martin Oettel
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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2
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Goodall REA, Lee AA. Data-driven approximations to the bridge function yield improved closures for the Ornstein-Zernike equation. SOFT MATTER 2021; 17:5393-5400. [PMID: 33969369 DOI: 10.1039/d1sm00402f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A key challenge for soft materials design and coarse-graining simulations is determining interaction potentials between components that give rise to desired condensed-phase structures. In theory, the Ornstein-Zernike equation provides an elegant framework for solving this inverse problem. Pioneering work in liquid state theory derived analytical closures for the framework. However, these analytical closures are approximations, valid only for specific classes of interaction potentials. In this work, we combine the physics of liquid state theory with machine learning to infer a closure directly from simulation data. The resulting closure is more accurate than commonly used closures across a broad range of interaction potentials.
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Affiliation(s)
| | - Alpha A Lee
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
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3
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Ramos F, Ramos A, Pellicane G, Lee LL. Construction of a composite-sphere model for molecules of tetrahedral symmetry. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1913254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Franklin Ramos
- Department of Chemical & Materials Engineering, California State University, Pomona, CA, USA
| | - Ana Ramos
- Department of Chemical & Materials Engineering, California State University, Pomona, CA, USA
| | - Giuseppe Pellicane
- Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali Università degli Studi di Messina, Messina, Italy
- CNR-IPCF, Messina, Italy
- School of Chemistry and Physics, University of Kwazulu-Natal, Pietermaritzburg, South Africa
- National Institute of Theoretical Physics (NIThEP), Pietermaritzburg, South Africa
| | - Lloyd L. Lee
- Department of Chemical & Materials Engineering, California State University, Pomona, CA, USA
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4
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Le T, Tran NT. The Nonlinear Decrement in Static Permittivity of Electrolytes in High-Polarity Solvents. J SOLUTION CHEM 2021. [DOI: 10.1007/s10953-020-01045-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Yuan G, Kienzle PA, Satija SK. Salting Up and Salting Down of Bovine Serum Albumin Layers at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15240-15246. [PMID: 33295178 DOI: 10.1021/acs.langmuir.0c02457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The surface adsorption of bovine serum albumin in pure water and salted aqueous solutions was studied by neutron reflection. With the contrast match technique, the surface excess in null reflecting water as a function of the protein concentration was revealed. It is found that, in a concentration range from 1 ppm (parts per million, mg/L) to 1000 ppm, without salts, the surface excess shows a profound peak at around 20 ppm; with salts, the surface excess increases steadily with the protein concentration. When the surface excess at a specific protein concentration is viewed, the introduction of sodium chloride causes either a salting down effect (surface adsorption decline) or a salting up effect (surface adsorption increase), depending upon the protein concentration. The salting up effect is observed at the low (∼1 ppm) and high (∼1000 ppm) concentrations, and the salting down effect dominates the intermediate concentration range. The change in solution pH relative to the isoelectric point (PI) can act as a simple indicator for the salting up or salting down behavior. When the solution pH is shifted toward the PI by adding salts, surface adsorption enhances; when the solution pH is shifted away from the PI by adding salts, surface adsorption declines.
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Affiliation(s)
- Guangcui Yuan
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Department of Physics, Georgetown University, Washington, D.C. 20057, United States
| | - Paul A Kienzle
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Sushil K Satija
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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6
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Starosta R, Santos FC, de Almeida RF. Human and bovine serum albumin time-resolved fluorescence: Tryptophan and tyrosine contributions, effect of DMSO and rotational diffusion. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128805] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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7
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Sønderby P, Söderberg C, Frankær CG, Peters G, Bukrinski JT, Labrador A, Plivelic TS, Harris P. Concentrated protein solutions investigated using acoustic levitation and small-angle X-ray scattering. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:396-404. [PMID: 32153278 DOI: 10.1107/s1600577519016977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 12/19/2019] [Indexed: 06/10/2023]
Abstract
An acoustically levitated droplet has been used to collect synchrotron SAXS data on human serum albumin protein solutions up to a protein concentration of 400 mg ml-1. A careful selection of experiments allows for fast data collection of a large amount of data, spanning a protein concentration/solvent concentration space with limited sample consumption (down to 3 µL per experiment) and few measurements. The data analysis shows data of high quality that are reproducible and comparable with data from standard flow-through capillary-based experiments. Furthermore, using this methodology, it is possible to achieve concentrations that would not be accessible by conventional cells. The protein concentration and ionic strength parameter space diagram may be covered easily and the amount of protein sample is significantly reduced (by a factor of 100 in this work). Used in routine measurements, the benefits in terms of protein cost and time spent are very significant.
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Affiliation(s)
- Pernille Sønderby
- Department of Chemistry, Technical University of Denmark, Kemitorvet B207, DK-2800 Kgs Lyngby, Denmark
| | | | - Christian G Frankær
- Deparment of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Günther Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet B207, DK-2800 Kgs Lyngby, Denmark
| | | | - Ana Labrador
- MAX IV Laboratory, Lund University, PO Box 118, 221 00 Lund, Sweden
| | - Tomás S Plivelic
- MAX IV Laboratory, Lund University, PO Box 118, 221 00 Lund, Sweden
| | - Pernille Harris
- Department of Chemistry, Technical University of Denmark, Kemitorvet B207, DK-2800 Kgs Lyngby, Denmark
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8
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Mkanya A, Pellicane G, Ramos FS, Ramos AM, Lee LL. On the structure, property, and phase behaviour of the symmetric Yukawa mixtures: testing of the consistent integral equation theories. Mol Phys 2019. [DOI: 10.1080/00268976.2018.1542165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Anele Mkanya
- School of Chemistry and Physics, University of Kwazulu-Natal, Pietermaritzburg, South Africa
- National Institute for Theoretical Physics (NITheP), KZN node, Pietermaritzburg, South Africa
| | - Giuseppe Pellicane
- School of Chemistry and Physics, University of Kwazulu-Natal, Pietermaritzburg, South Africa
- National Institute for Theoretical Physics (NITheP), KZN node, Pietermaritzburg, South Africa
| | - Franklin S. Ramos
- Department of Chemical and Materials Engineering, California State University, Pomona, CA, USA
| | - Ana M. Ramos
- Department of Chemical and Materials Engineering, California State University, Pomona, CA, USA
| | - Lloyd L. Lee
- School of Chemistry and Physics, University of Kwazulu-Natal, Pietermaritzburg, South Africa
- Department of Chemical and Materials Engineering, California State University, Pomona, CA, USA
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9
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Mbuyise XG, Arbab EAA, Mola GT. The effect of a trimetallic nanocomposite in the solar absorber layer of organic solar cells. RSC Adv 2019; 9:6070-6076. [PMID: 35517268 PMCID: PMC9060879 DOI: 10.1039/c8ra08725c] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 01/22/2019] [Indexed: 12/18/2022] Open
Abstract
Bulk heterojunction (BHJ) organic solar cells were fabricated using a trimetallic nanocomposite (Ag : Zn : Ni) in the photoactive layer. The incorporation of the nanocomposite was limited to the concentrations of 4% and 6% by volume into poly(3-hexylthiophene) (P3HT) and 6-6-phenyl-C61-butyric acid methyl ester (PCBM) blend solar absorber. The newly fabricated devices were investigated in terms of the optical, electrical and morphological properties of the photoactive medium. The power conversion efficiencies (PCE) of the solar cells were found to be increased by 57% and 84% due to improved harvesting of solar radiation due to the occurrence of localized surface plasmon resonance (LSPR) effects of the metal nanocomposite. Silver : zinc : nickel (Ag : Zn : Ni) tri-metallic nanocomposites were synthesized using a chemical reduction method from silver, zinc and nickel nitrates. The nanocomposites were characterized in terms of morphology, elemental composition and crystallinity which are extensively discussed in the manuscript. Bulk heterojunction (BHJ) organic solar cells were fabricated using a trimetallic nanocomposite (Ag : Zn : Ni) in the photoactive layer.![]()
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Affiliation(s)
- Xolani G. Mbuyise
- School of Chemistry & Physics
- University of KwaZulu-Natal
- Scottsville 3209
- South Africa
| | - Elhadi A. A. Arbab
- School of Chemistry & Physics
- University of KwaZulu-Natal
- Scottsville 3209
- South Africa
- Department of Physics
| | - Genene Tessema Mola
- School of Chemistry & Physics
- University of KwaZulu-Natal
- Scottsville 3209
- South Africa
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10
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Sønderby P, Bukrinski JT, Hebditch M, Peters GHJ, Curtis RA, Harris P. Self-Interaction of Human Serum Albumin: A Formulation Perspective. ACS OMEGA 2018; 3:16105-16117. [PMID: 30556026 PMCID: PMC6288999 DOI: 10.1021/acsomega.8b02245] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 11/13/2018] [Indexed: 05/12/2023]
Abstract
In the present study, small-angle X-ray scattering (SAXS) and static light scattering (SLS) have been used to study the solution properties and self-interaction of recombinant human serum albumin (rHSA) molecules in three pharmaceutically relevant buffer systems. Measurements are carried out up to high protein concentrations and as a function of ionic strength by adding sodium chloride to probe the role of electrostatic interactions. The effective structure factors (S eff) as a function of the scattering vector magnitude q have been extracted from the scattering profiles and fit to the solution of the Ornstein-Zernike equation using a screened Yukawa potential to describe the double-layer force. Although only a limited q range is used, accurate fits required including an electrostatic repulsion element in the model at low ionic strength, while only a hard sphere model with a tunable diameter is necessary for fitting to high-ionic-strength data. The fit values of net charge agree with available data from potentiometric titrations. Osmotic compressibility data obtained by extrapolating the SAXS profiles or directly from SLS measurements has been fit to a 10-term virial expansion for hard spheres and an equation of state for hard biaxial ellipsoids. We show that modeling rHSA as an ellipsoid, rather than a sphere, provides a much more accurate fit for the thermodynamic data over the entire concentration range. Osmotic virial coefficient data, derived at low protein concentration, can be used to parameterize the model for predicting the behavior up to concentrations as high as 450 g/L. The findings are especially important for the biopharmaceutical sector, which require approaches for predicting concentrated protein solution behavior using minimal sample consumption.
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Affiliation(s)
- Pernille Sønderby
- Department
of Chemistry, Technical University of Denmark, Building 207, DK-2800 Kgs. Lyngby, Denmark
| | - Jens T. Bukrinski
- Novozymes
Biopharma A/S, Krogshøjvej
36, Bagsværd, DK-2880 Copenhagen, Denmark
| | - Max Hebditch
- School
of Chemical Engineering and Analytical Science, The University of Manchester, Sackville Street, Manchester M13 9PL, U.K.
| | - Günther H. J. Peters
- Department
of Chemistry, Technical University of Denmark, Building 207, DK-2800 Kgs. Lyngby, Denmark
| | - Robin A. Curtis
- School
of Chemical Engineering and Analytical Science, The University of Manchester, Sackville Street, Manchester M13 9PL, U.K.
- E-mail: (R.A.C.)
| | - Pernille Harris
- Department
of Chemistry, Technical University of Denmark, Building 207, DK-2800 Kgs. Lyngby, Denmark
- E-mail: (P.H.)
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11
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Prestipino S, Munaò G, Costa D, Caccamo C. Self-assembly in a model colloidal mixture of dimers and spherical particles. J Chem Phys 2018; 146:084902. [PMID: 28249437 DOI: 10.1063/1.4976704] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We investigate the structure of a dilute mixture of amphiphilic dimers and spherical particles, a model relevant to the problem of encapsulating globular "guest" molecules in a dispersion. Dimers and spheres are taken to be hard particles, with an additional attraction between spheres and the smaller monomers in a dimer. Using the Monte Carlo simulation, we document the low-temperature formation of aggregates of guests (clusters) held together by dimers, whose typical size and shape depend on the guest concentration χ. For low χ (less than 10%), most guests are isolated and coated with a layer of dimers. As χ progressively increases, clusters grow in size becoming more and more elongated and polydisperse; after reaching a shallow maximum for χ≈50%, the size of clusters again reduces upon increasing χ further. In one case only (χ=50% and moderately low temperature) the mixture relaxed to a fluid of lamellae, suggesting that in this case clusters are metastable with respect to crystal-vapor separation. On heating, clusters shrink until eventually the system becomes homogeneous on all scales. On the other hand, as the mixture is made denser and denser at low temperature, clusters get increasingly larger until a percolating network is formed.
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Affiliation(s)
- Santi Prestipino
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Gianmarco Munaò
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Dino Costa
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Carlo Caccamo
- Dipartimento di Scienze Matematiche ed Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
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12
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Haghmoradi A, Wang L, Chapman WG. A density functional theory for association of fluid molecules with a functionalized surface: fluid-wall single and double bonding. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:044002. [PMID: 27897149 DOI: 10.1088/1361-648x/29/4/044002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In this manuscript we extend Wertheim's two-density formalism beyond its first order to model a system of fluid molecules with a single association site close to a planar hard wall with association sites on its surface in a density functional theory framework. The association sites of the fluid molecules are small enough that they can form only one bond, while the wall association sites are large enough to bond with more than one fluid molecule. The effects of temperature and of bulk fluid and wall site densities on the fluid density profile, extent of association, and competition between single and double bonding of fluid segments at the wall sites versus distance from the wall are presented. The theory predictions are compared with new Monte Carlo simulation results and they are in good agreement. The theory captures the surface coverage over wide ranges of temperature and bulk density by introducing the effect of steric hindrance in fluid association at a wall site.
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Affiliation(s)
- Amin Haghmoradi
- Chemical and Biomolecular Engineering Department, Rice University, Houston, TX, USA
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13
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Delivery of Copper-chelating Trientine (TETA) to the central nervous system by surface modified liposomes. Int J Pharm 2016; 512:87-95. [PMID: 27553779 DOI: 10.1016/j.ijpharm.2016.08.040] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/12/2016] [Accepted: 08/18/2016] [Indexed: 01/06/2023]
Abstract
The existence of the blood-brain barrier (BBB) complicates the treatment of many central nervous system (CNS) disorders, including the copper storage disease, Wilson's disease. Its CNS symptoms represent a serious problem, since therapeutics for Wilson's disease do not cross the BBB. One strategy to overcome this obstacle is the transfer of drugs across the BBB with colloidal carrier systems like liposomes. The aim of the present study was to encapsulate triethylenetetramine (TETA), a copper chelating agent, into surface modified liposomes and to investigate their permeation across the BBB. Liposomes were modified with cationized bovine serum albumin or penetratin, a cell penetrating peptide. Liposomes were characterized regarding size, PDI, zeta potential and encapsulation efficiency. Size was between 139.4±1.9nm to 171.1±3.5nm with PDI's below 0.2. Zeta potentials of vectorized liposomes were at least 6.9mV higher than those of standard liposomes. Cryo-TEM micrographs displayed liposomal structure, integrity and the similarity of structure and size between loaded, unloaded, vectorized and non- vectorized liposomes. In vivo experiments in rats showed an up to 16-fold higher brain uptake of TETA in vectorized liposomes compared to free TETA or TETA in non-vectorized liposomes, proving successful brain delivery using target seeking surface modifications. Tissue analysis indicated TETA concentrations in the brain being high enough to treat Wilson's disease.
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14
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Gavish N, Promislow K. Dependence of the dielectric constant of electrolyte solutions on ionic concentration: A microfield approach. Phys Rev E 2016; 94:012611. [PMID: 27575183 DOI: 10.1103/physreve.94.012611] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Indexed: 06/06/2023]
Abstract
We present a microfield approach for studying the dependence of the orientational polarization of the water in aqueous electrolyte solutions upon the salt concentration and temperature. The model takes into account the orientation of the solvent dipoles due to the electric field created by ions, and the effect of thermal fluctuations. The model predicts a dielectric functional dependence of the form ɛ(c)=ɛ_{w}-βL(3αc/β),β=ɛ_{w}-ɛ_{ms}, where L is the Langevin function, c is the salt concentration, ɛ_{w} is the dielectric of pure water, ɛ_{ms} is the dielectric of the electrolyte solution at the molten salt limit, and α is the total excess polarization of the ions. The functional form gives a remarkably accurate description of the dielectric constant for a variety of salts and a wide range of concentrations.
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Affiliation(s)
- Nir Gavish
- Mathematics Department, Technion - Israel Institute of Technology, Haifa, 32000, Israel
| | - Keith Promislow
- Department of Mathematics, Michigan State University, East Lansing, Michigan 48864, USA
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15
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Polypeptide-Nanoparticle Interactions and Corona Formation Investigated by Monte Carlo Simulations. Polymers (Basel) 2016; 8:polym8060203. [PMID: 30979300 PMCID: PMC6432162 DOI: 10.3390/polym8060203] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 12/23/2022] Open
Abstract
Biomacromolecule activity is usually related to its ability to keep a specific structure. However, in solution, many parameters (pH, ionic strength) and external compounds (polyelectrolytes, nanoparticles) can modify biomacromolecule structure as well as acid/base properties, thus resulting in a loss of activity and denaturation. In this paper, the impact of neutral and charged nanoparticles (NPs) is investigated by Monte Carlo simulations on polypeptide (PP) chains with primary structure based on bovine serum albumin. The influence of pH, salt valency, and NP surface charge density is systematically studied. It is found that the PP is extended at extreme pH, when no complex formation is observed, and folded at physiological pH. PP adsorption around oppositely-charged NPs strongly limits chain structural changes and modifies its acid/base properties. At physiological pH, the complex formation occurs only with positively-charged NPs. The presence of salts, in particular those with trivalent cations, introduces additional electrostatic interactions, resulting in a mitigation of the impact of negative NPs. Thus, the corona structure is less dense with locally-desorbed segments. On the contrary, very limited impact of salt cation valency is observed when NPs are positive, due to the absence of competitive effects between multivalent cations and NP.
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16
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Shimizu S, Matubayasi N. The origin of cooperative solubilisation by hydrotropes. Phys Chem Chem Phys 2016; 18:25621-25628. [DOI: 10.1039/c6cp04823d] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The signature of hydrotropic solubilisation is the sigmoidal solubility curve; when plotted against hydrotrope concentration, solubility increases suddenly after the minimum hydrotrope concentration (MHC), and reaches a plateau at higher hydrotrope concentrations. Here we explain the origin of hydrotropic cooperativity based on statistical thermodynamics.
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Affiliation(s)
- Seishi Shimizu
- York Structural Biology Laboratory
- Department of Chemistry
- University of York
- York YO10 5DD
- UK
| | - Nobuyuki Matubayasi
- Division of Chemical Engineering
- Graduate School of Engineering Science
- Osaka University
- Osaka 560-8531
- Japan
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17
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Glibitskiy G, Glibitskiy D, Gorobchenko O, Nikolov O, Roshal A, Semenov M, Gasan A. Textures on the surface of BSA films with different concentrations of sodium halides and water state in solution. NANOSCALE RESEARCH LETTERS 2015; 10:155. [PMID: 25897305 PMCID: PMC4395624 DOI: 10.1186/s11671-015-0860-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/11/2015] [Indexed: 06/04/2023]
Abstract
The formation of the textures on the surface of the films from the solutions of bovine serum albumin (BSA) with sodium halides (NaF, NaCl, and NaBr) of various concentrations was studied. The formation of symmetric zigzag textures on the surface of BSA films (Cryst Eng 3:173-194, 2000) in the presence of sodium halides depends on the conformational state of the protein globule. Thermal denaturation of BSA also did not allow to form zigzag textures on the surface of the films.
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Affiliation(s)
- Gennadiy Glibitskiy
- />A.Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12, Academician Proskura Str, Kharkiv, 61085 Ukraine
| | - Dmitriy Glibitskiy
- />A.Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12, Academician Proskura Str, Kharkiv, 61085 Ukraine
| | - Olga Gorobchenko
- />Department of Molecular and Medical Biophysics, School of Radiophysics, V.N. Karazin Kharkiv National University, 4 Svobody Sq, Kharkiv, 61022 Ukraine
| | - Oleg Nikolov
- />Department of Molecular and Medical Biophysics, School of Radiophysics, V.N. Karazin Kharkiv National University, 4 Svobody Sq, Kharkiv, 61022 Ukraine
| | - Alexander Roshal
- />Institute for Chemistry, V.N. Karazin Kharkiv National University, 4 Svobody Sq, Kharkiv, 61022 Ukraine
| | - Mikhail Semenov
- />A.Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12, Academician Proskura Str, Kharkiv, 61085 Ukraine
| | - Anatoliy Gasan
- />A.Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of Ukraine, 12, Academician Proskura Str, Kharkiv, 61085 Ukraine
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Benrezkallah D, Dauchez M, Krallafa A. Molecular dynamics of the salt dependence of a cold-adapted enzyme: endonuclease I. J Biomol Struct Dyn 2015; 33:2511-21. [DOI: 10.1080/07391102.2014.1002007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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