Serum Albumin In Aqueous Solution Research Articles

Optical Study of the Influence of the Medium Acidity on the Interaction between Gold Nanoparticles and Bovine Serum Albumin in Aqueous Solution

Optical Study of the Influence of the Medium Acidity on the Interaction between Gold Nanoparticles and Bovine Serum Albumin in Aqueous Solution

Albumin-induced large fluorescence turn ON in 4-(diphenylamino)benzothiazolium dyes for clinical applications in protein detection

A series of [4-(diphenylamino)]styrylbenzothiazolium-based fluorescent probes 1a -1f have been synthesized to investigate their albumin binding properties. The probe 1 was found to be nearly non-fluorescent in both aqueous and organic solvents and exhibited a very large fluorescence turn ON at λem ≈ 630–650 nm (фfl ≈0.38–0.40) upon addition of serum albumin in aqueous solution. Probes exhibited high sensitivity towards detecting albumin in aqueous solution with a limit of detection (LOD) below 7–14 ng/mL. The stability constants for the probe-albumin interactions were calculated by Stern-Volmer method. The stability of the probe-albumin complexes was further investigated during this study to understand the role of the substituents of the probe’s structure towards the observed selectivity. Spectrometric fluorescence titrations were conducted to investigate selectivity, sensitivity, and stability of the probe-albumin complex. Probe’s binding specificity was further studies in the presence of known site-specific drug molecules via competitive displacement method. The large fluorescence response exhibited towards HSA and BSA found to be highly useful for visualizing albumin content in SDS-PAGE up to nanogram scale. The probe 1 was successfully utilized for analysing albumin content in urine samples, showing good linear correlation and indicating the probe’s suitability in clinical diagnostics.

Analyzing the Size of Albumin Macromolecules in Aqueous Solutions

Changes in the structure and size of macromolecules of human and bovine serum albumin in aqueous solutions are considered, depending on temperature, concentration, and acid–base equilibrium. It is found that a change in the hydrodynamic radius of the macromolecule is an indicator of the structural phase transformations of globular proteins. Ways of determining the radii of macromolecules from data on the shear viscosity of solutions and the self-diffusion of macromolecules in them are discussed. The hydrodynamic radii of albumin macromolecules found by these means are compared. It is shown that conclusions can be drawn about the nature of bonding between water molecules and protein macromolecules using the obtained data.

Antifouling performance enhancement of polyethersulfone ultrafiltration membrane through increasing charge‐loading capacity over Prussian blue nanoparticles

AbstractPrussian blue (PB), as a kind of regulator of charge‐loading capacity, was first used to modify polyethersulfone (PES) membrane, and a novel PB/PES ultrafiltration membrane was prepared by non‐solvent induced phase separation method. The physicochemical properties of PB‐NPs and PB/PES membranes were analyzed by Fourier‐transform infrared spectroscopy, X‐ray diffraction, scanning electron microscope, atomic force microscope, and zeta potential analysis. It was observed that PB‐NPs were uniformly distributed in the PES matrix and a lotus‐seedpod structure was formed inside the membrane. The addition of PB‐NPs improved the charge‐loading capacity of the PES membrane. The permeation and antifouling performance were investigated by filtering bovine serum albumin aqueous solution with different pH values. The results showed that the PB/PES membrane with 0.2‐wt% PB‐NPs content had the excellent antifouling performance and the flux recovery ratio value reached 90.73%. Moreover, the long‐term stability test showed that PB‐NPs did not fall off after continuous pure water filtration, indicating that PB/PES membrane had a good stability.

Binding of pyridoxal, pyridoxal 5'-phosphate and derived hydrazones to bovine serum albumin in aqueous solution.

In the present paper, the kinetics of a reaction between bovine serum albumin (BSA) and pyridoxal, pyridoxal 5'-phosphate was studied, apparent rate constant of product formation and dissociation as well as binding constants were determined. Pyridoxal 5'-phosphate hydrazones of isonicotinic, picolinic, 2-furoic, thiophene-2-carboxylic, pyrazinoic acids binding to BSA was studied by spectrofluorimetry, stability constants of the associates were calculated from experimental data using maximal likelihood approach. The changes in the secondary structure of BSA induced by hydrazones addition were studied by IR spectroscopy. New freely available software for curve fitting was developed as a part of the software kit designed for the solution chemistry and used for a specific problem of this study, IR spectra processing.

Constants of the Formation of Complexes with Nanomarkers of the Fluorescein Family and Bovine Serum Albumin in Aqueous Solutions

The formation of complexes with nanomarkers of the fluorescein family and BSA in aqueous solutions is studied and its constants are determined. Three different models are plotted to interpret the experimental data. The effect of saturating a complex of nanomarkers and BSA, the presence of negative cooperativity in complexation, and the dependence of complexation on the mutual combination of the values of electrostatic charges on the protein and nanomarkers are found and explained using these models. The parameter of nanomarker affinity toward BSA during complexation is calculated.

A Vertical Flow Method for Sensitive Raman Protein Measurement in Aqueous Solutions.

Raman scattering is intrinsically faint. Raman spectroscopy would be more valuable with improvements in the signal detection efficiency. To improve the signal detection efficiency, we propose a vertical flow method, which is a derivative of the liquid core optical fiber technique employed for sensitive Raman signal detection. In the vertical flow method, the sample solution flows from a pinhole to prepare a liquid column wrapped with air and uses total reflection at the sample-air interface to confine the excitation beam and Raman signal. The Raman signal emerges from the pinhole for efficient collection. This method enhanced Raman signal intensity by up to 90 times. When measuring a bovine serum albumin aqueous solution, the limit of detection (LOD) was 0.029 ± 0.003 mg mL-1 (0.44 ± 0.05 μM). We discuss the signal enhancement factor dependence on several parameters in the vertical flow method. Our method provides a simple technique to improve Raman spectroscopy sensitivity using universal materials.

Белок-полиэлектролитные комплексы. Часть 3. Комплексы бычьего сывороточного альбумина с сульфонатсодержащими ароматическими поли- и сополиамидами

The interaction of bovine serum albumin in aqueous solution with sulfonate-containing poly- and copolyamides were studied. It was shown that, as a result of macromolecular reactions protein-polyelectrolyte complexes forms, stabilized mainly by electrostatic forces. To characterize the protein-polyelectrolyte complexes composition the r parameter used, which is defines as the ratio of mass concentration of polyelectrolyte and protein. It was shown that the main factor determining the composition and structure of forming protein-polyelectrolyte complexes is the degree of ionization of functional groups, interacting in the polyelectrolyte reaction that is determined by the nature of those groups and the pH of the solution. The presen ce of sulfonate and carboxylic groups in the copolyamide composition gives an extra opportunity to regulate the protein-polyelectrolyte interactions. Using spectrophotometry were established that, in the studied system when the aromatic polyamide and bovine serum albumin are mixed at optimal pH conditions (рН < 4.9), complexes are formed, the composition of which corresponds to the value of r ~ 0.15 g/g. The degree of conversation in protein-polyelectrolyte reactions is close to 0.8. The size of the formed particles was about 2.2 μm. In the case of aromatic copolyamides that contain both sulfonate and carboxylic groups, an increase in concentration of carboxylic groups to 42 mol. % leads to a shift of the optical density maximum on the curve of turbidimetric titration in to the higher r values (~ 0.18 g/g) at pH = 3.5, when the carboxylic groups are non-ionized. The size of the formed complex particles was about ~ 150.0 nm, the fraction of micron-sized particles is about 5%. The degree of released protein is based on the conditions under which reaction take place and varies from 93 to 99%. The result obtained during this work can serve as a base for the effective methods of isolation and purifying of the target proteins development.

Influence of pH and Salts on Partial Molar Volume of Lysozyme and Bovine Serum Albumin in Aqueous Solutions.

The partial molar volume of lysozyme and bovine serum albumin in aqueous solutions at different pH values and in aqueous solutions containing sodium chloride, ammonium chloride, sodium sulfate, or ammonium sulfate at different concentrations at pH 7.0 was investigated experimentally at 298.15 K and 1 bar. It was found that the influence of the pH value and the salts on the partial molar volume of the proteins is small, but trends were measurable. Furthermore, the partial molar volume of lysozyme in pure water at different pH values and in aqueous solutions with different sodium chloride concentrations at pH 7.0 was predicted by molecular simulations. The predictions are in good agreement with the experimental data.

Polypropylene composite hollow fiber ultrafiltration membranes with an acrylic hydrogel surface by in situ ultrasonic wave‐assisted polymerization for dye removal

ABSTRACTIn this study, polypropylene composite hollow fiber membrane with an acrylic hydrogel layer was fabricated successfully by in situ ultrasonic wave‐assisted polymerization. The ultrasonic irradiation can significantly improve the grafting efficiency of acrylic acid on the membrane surface. The modified membranes were characterized on the basis of physicochemical characteristics, permeation performance and antifouling property. The results revealed that the pure water flux of modified membranes was significantly increased when the graft density was lower than 0.82 mg cm−2, due to the improvement of hydrophilicity. Interestingly, the optimized membrane PPM1.49 could efficiently remove organic dyes from aqueous solution, showing retentions of 99.5 and 98.7% to Congo red and methylthionine chloride, respectively. Meanwhile, its flux recovery ratio was elevated from 68.0 to 92.0% using bovine serum albumin aqueous solution as a foulant compared with the pristine membrane. These promising results indicate that modified membranes developed in this study are potentially applicable for dye removal from wastewater. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47099.

Interaction of proteins with ionic liquid, alcohol and DMSO and in situ generation of gold nano-clusters in a cell.

In this review, we give a brief overview on how the interaction of proteins with ionic liquids, alcohols and dimethyl sulfoxide (DMSO) influences the stability, conformational dynamics and function of proteins/enzymes. We present experimental results obtained from fluorescence correlation spectroscopy on the effect of ionic liquid or alcohol or DMSO on the size (more precisely, the diffusion constant) and conformational dynamics of lysozyme, cytochrome c and human serum albuminin aqueous solution. The interaction of ionic liquid with biomolecules (e.g. protein, DNA etc.) has emerged as a current frontier. We demonstrate that ionic liquids are excellent stabilizers of protein and DNA and, in some cases, cause refolding of a protein already denatured by chemical denaturing agents. We show that in ethanol-water binary mixture, proteins undergo non-monotonic changes in size and dynamics with increasing ethanol content. We also discuss the effect of water-DMSO mixture on the stability of proteins. We demonstrate how large-scale molecular dynamics simulations have revealed the molecular origin of this observed phenomenon and provide a microscopic picture of the immediate environment of the biomolecules. Finally, we describe how favorable interactions of ionic liquids may be utilized for in situ generation of fluorescent gold nano-clusters for imaging a live cell.

Carbon Nanotubes Facilitate Oxidation of Cysteine Residues of Proteins.

The adsorption of proteins onto nanoparticles such as carbon nanotubes (CNTs) governs the early stages of nanoparticle uptake into biological systems. Previous studies regarding these adsorption processes have primarily focused on the physical interactions between proteins and nanoparticles. In this study, using reduced lysozyme and intact human serum albumin in aqueous solutions, we demonstrated that CNTs interact chemically with proteins. The CNTs induce the oxidation of cysteine residues of the proteins, which is accounted for by charge transfer from the sulfhydryl groups of the cysteine residues to the CNTs. The redox reaction simultaneously suppresses the intermolecular association of proteins via disulfide bonds. These results suggest that CNTs can affect the folding and oxidation degree of proteins in biological systems such as blood and cytosol.

Separation and antifouling properties of hydrolyzed PAN hybrid membranes prepared via in-situ sol-gel SiO2 nanoparticles growth

In this work, a novel approach of hydrolysis followed by in-situ sol-gel of tetraethyl orthosilicate (TEOS) was developed to modify the polyacrylonitrile (PAN) porous membrane prepared via non-solvent induced phase separation technique for improved separation and antifouling properties. PAN/SiO2 hybrid membranes prepared using different contents of TEOS were characterized through ATR-FTIR, XPS, SEM, EDS, water contact angle measurement, cross-flow permeation test, static protein adsorption test and dynamic cross-flow protein fouling experiment. It was found that the sol-gel of TEOS took placed both on membrane surface and within membrane pore and the generated SiO2 particles affected both membrane surface and permeation properties through the roles of surface deposition and pore-filling, respectively. The in-situ sol-gel of TEOS could efficiently improve membrane separation property through tuning pore size and narrowing pore size distribution. Compared with the base and hydrolyzed PAN membranes of same water permeability, the PAN/SiO2 hybrid membrane exhibited a much lower molecular weight cut-off and thus enhanced rejection performance. Furthermore, both static protein adsorption and dynamic cross-flow fouling experiments with bovine serum albumin aqueous solution demonstrated that the surface deposition of SiO2 could appreciably improve membrane antifouling property through making membrane surface more hydrophilic, negatively charged and enriched with hydroxyl groups.

Studies on the Interaction of Cefepime Hydrochloride with Bovine Serum Albumin by Fluorescence, Synchronous Fluorescence, Three-Dimensional Fluorescence and Circular Dichroism

The investigation on the binding mode between drug and protein is extremely important to understand biopharmaceutics, pharmacokinetics and toxicity of the drug as well as the relationship of structure and function of the protein. It is well proved that biological activity is a function of the chemical structure or structural properties. There is a study on the interaction of cefepime hydrochloride with serum albumin using in-silico molecular docking. But up to date, there is hardly any interaction investigation of cefepime hydrochloride with serum albumin utilizing by fluorescence, synchronous fluorescence, three-dimensional fluorescence and circular dichroism. In this study, the interaction of cefepime hydrochloride with bovine serum albumin in aqueous solution has been investigated by molecular spectroscopy under different pH conditions. The quenching rate constant and binding constant calculated at pH 7.4 indicated the static quenching mechanism and medium binding force. The effect of cefepime hydrochloride on the conformation of bovine serum albumin was analyzed using fluorescence, synchronous fluorescence, threedimensional fluorescence and circular dichroism. In addition, influence of pH on the binding of cefepime hydrochloride to bovine serum albumin was investigated and the binding ability of the drug to bovine serum albumin deceased under other pH conditions (pH 1.9, 3.5, and 9.0) as compared with that at pH 7.4. As compared with the binding ability of cefepime hydrochloride to native bovine serum albumin that of cefepime hydrochloride to denatured bovine serum albumin deceases dramatically. Furthermore, the effect of metal ions on the binding constant of cefepime hydrochloride with bovine serum albumin was investigated.

Thermally induced conformational changes and protein-protein interactions of bovine serum albumin in aqueous solution under different pH and ionic strengths as revealed by SAXS measurements.

Thermal-induced conformational changes and protein-protein interactions of bovine serum albumin (BSA) in aqueous solution are assessed by small angle X-ray scattering (SAXS) at two pH values (7.4 and 9.0) and two ionic strengths (0.1 and 0.5). We demonstrate that Guinier analysis in two ranges of the modulus of the scattering vector allows protein melting and aggregation to be monitored simultaneously, thus providing insights into the mechanism of thermal-induced BSA aggregation. Results of the analysis suggest that at room temperature monomeric and dimeric BSA fractions are present in solution. For low concentrations (<10 mg mL-1) the monomeric to dimeric fraction ratio is close to 6, the same value we obtained independently in size-exclusion chromatography experiments. For elevated concentrations (20 mg mL-1 and 40 mg mL-1) a decrease in the dimer fraction occurs. Following heating, dimer formation is observed prior to protein melting, while no higher order aggregates are observed in the 20-60 °C temperature range. In the vicinity of the BSA melting point, higher order aggregates appear and protein molecules exhibit an aggregation burst. Higher ionic strength makes the described effects more pronounced - dimer formation increases at lower temperatures, presumably due to partial screening of electrostatic interactions between protein molecules. Moreover, the melting temperature shifts to higher values upon increasing the protein concentration and pH, indicating that repulsive interactions stabilize the protein structure. The suggested model was verified by the assessment of parameters of protein-protein interaction potentials based on DLVO theory using the global fitting procedure.

Self-assembling of poly(aspartic acid) with bovine serum albumin in aqueous solutions

Macromolecular co-assemblies built up in aqueous solutions, by using a linear polypeptide, poly(aspartic acid) (PAS), and a globular protein, bovine serum albumin (BSA), have been studied. The main interest was to identify the optimum conditions for an interpenetrated complex formation in order to design materials suitable for biomedical applications, such as drug delivery systems. BSA surface possesses several amino- and carboxylic groups available for covalent modification, and/or bioactive substances attachment. In the present study, mixtures between PAS and BSA were investigated at 37°C in dilute aqueous solution by viscometry, dynamic light scattering and zeta potential determination, as well as in solid state by AFM microscopy and dielectric spectroscopy. The experimental data have shown that the interpolymer complex formation occurs for a PAS/BSA molar ratio around 0.541.

Investigating the Structural Change in Protein Aqueous Solution Using Temperature-Dependent Near-Infrared Spectroscopy and Continuous Wavelet Transform.

The circulatory protein, human serum albumin (HSA), is widely used as a model protein for the study of protein structure. In this work, the structures of human serum albumin in aqueous solutions are studied using temperature-dependent near-infrared (NIR) spectroscopy with the aid of continuous wavelet transform (CWT). Near-infrared spectra of human serum albumin solutions with different concentrations were measured over a temperature range of 30-85 ℃. Then, continuous wavelet transform was performed on the spectra to enhance the resolution. As a result of the resolution enhancement, spectral bands around 4361, 4521, 4600 and 4260 cm-1 were extracted from the overlapping low-resolution signals. The four bands can be assigned to the protein structures of α-helix, β-sheet, an intermediate state and side chains, respectively. The variations in intensity of the bands around 4361 and 4521 cm-1 with temperature show that the increase of temperature leads to the loss of α-helical structure but the formation of β-sheet, and the denaturation temperature of human serum albumin is about 55 ℃. The variation of the band around 4600 cm-1 indicates that the temperature-induced unfolding process of human serum albumin occurs through a stable intermediate state, and a significant change in the microenvironment of the side chains about 63 ℃ is observed from the variation of the band around 4260 cm-1. On the other hand, the transformed spectra in the region of 8000-5600 cm-1 provide an explicit evidence for the structural changes of water during the process of protein denaturation, and the unfolding process of HSA can be reflected by these changes.

Solvatochromic fluorescent probes for recognition of human serum albumin in aqueous solution: Insights into structure-property relationship

Human serum albumin (HSA) as the most abundant protein in human blood plasma, serves many physiological functions. The dysregulation of HSA in serum or in urine is associated with various diseases, such as cirrhosis of liver, multiple myeloma, and cardiovascular disease. Therefore, to quantify HSA in body fluids with high selectivity and sensitivity is of great significance for disease diagnosis and preventive medicine. We herein developed a series of amide-functionalized flavonoids probes, 1–3, for recognition of human serum albumin. All flavonoids could be easily prepared by a Claisen-Schmidt condensation and Algar-Flynn-Oyamada reaction, and showed positive solvatochromism on their dual emissions. The chemical structure of flavonoids played an important role on their HSA-sensing abilities. Among three probes, the compound 1 showed the highest sensitivity, the remarkable selectivity, and the quantitive response for HSA in aqueous solution. Together with its high tolerance of environmental pH, anti-interference properties, and time-insensitivity, thus it provides a promising sensing method for HSA.

Impact of Ice Morphology on Design Space of Pharmaceutical Freeze-Drying

It has been known that the sublimation kinetics of a freeze-drying product is affected by its internal ice crystal microstructures. This article demonstrates the impact of the ice morphologies of a frozen formulation in a vial on the design space for the primary drying of a pharmaceutical freeze-drying process. Cross-sectional images of frozen sucrose–bovine serum albumin aqueous solutions were optically observed and digital pictures were acquired. Binary images were obtained from the optical data to extract the geometrical parameters (i.e., ice crystal size and tortuosity) that relate to the mass-transfer resistance of water vapor during the primary drying step. A mathematical model was used to simulate the primary drying kinetics and provided the design space for the process. The simulation results predicted that the geometrical parameters of frozen solutions significantly affect the design space, with large and less tortuous ice morphologies resulting in wide design spaces and vice versa. The optimal applicable drying conditions are influenced by the ice morphologies. Therefore, owing to the spatial distributions of the geometrical parameters of a product, the boundary curves of the design space are variable and could be tuned by controlling the ice morphologies.

Exploration of interactions between decyl-β-d-glucopyranoside and bovine serum albumin in aqueous solution

The interactions between decyl-β-d-glucopyranoside (DG) and bovine serum albumin (BSA), in aqueous media, were investigated through the use of surface tension, steady-state fluorescence, and UV-vis absorption spectroscopy measurements.