Adsorption Behavior Of Bovine Serum Albumin Research Articles

Stability of Liquid Films Formed by a Single Bubble and Droplet at Liquid/Gas and Liquid/Liquid Interfaces in Bovine Serum Albumin Solutions.

The properties of thin liquid films are usually investigated under static conditions, isolated from external disturbances. Such studies provide vital information about the drainage mechanism of the thin liquid film, but the conditions of these measurements are vastly different from those that occur when a real dispersed system is created. In this paper, we present elaborated methodologies that allow qualitative and quantitative measurements of the stability of both the emulsion and foam films formed by a single bubble and droplet at liquid/gas and liquid/liquid interfaces, where the hydrodynamic factors are of crucial importance. The experiments were performed in a bovine serum albumin (BSA) solution at different pH values. The adsorption behavior of BSA under different pH conditions at the liquid/gas and liquid/liquid interface is described, and its implication for the single bubble/droplet motion and liquid film drainage is analyzed. The mechanism of thin-liquid-film stabilization by the BSA molecules is shown to be significantly different for the foam and emulsion films and depends significantly on the bubble history as well as the pH of the BSA solution. Additionally, the results obtained for BSA were compared to those acquired for a typical surface-active substance, sodium lauryl sulfate. The similarities and differences in the rising bubble/droplet dynamics (caused by different dynamic adsorption layer architectures) and foam and emulsion film stabilization by these two types of stabilizers under dynamic conditions are shown and discussed.

Preparation of Barbed ZnO Fibers and the Selective Adsorption Behavior for BSA.

ZnO electrospun nanofibers can act as seed fibers to fabricate multidentate barbed fibers perpendicular to the growth of the fibers using the chemical bath deposition (CBD) method. Fibers with a multirod morphology have a porous grid structure. The sample is easy to recover, and the nonpolar surface in the sample is sufficiently exposed. In the research of barbed fiber fabrication and adsorption on bovine serum albumin (BSA), the effects of different chemical bath conditions on the growth of ZnO nanorods were discussed. Barbed fibers with large slenderness ratios were obtained at a water content of 60 mL at 75 °C. Each milligram of barbed fibers can quickly adsorb about 162 μg of protein within 30 min. The adsorption activity of BSA between polar and nonpolar ZnO surfaces was also studied. The selective adsorption behavior of BSA on the nonpolar surface was revealed.

Elucidating How Different Amphipathic Stabilizers Affect BSA Protein Conformational Properties and Adsorption Behavior.

Natural proteins such as bovine serum albumin (BSA) are readily extracted from biological fluids and widely used in various applications such as drug delivery and surface coatings. It is standard practice to dope BSA proteins with an amphipathic stabilizer, most commonly fatty acids, during purification steps to maintain BSA conformational properties. There have been extensive studies investigating how fatty acids and related amphiphiles affect solution-phase BSA conformational properties, while it is far less understood how amphipathic stabilizers might influence noncovalent BSA adsorption onto solid supports, which is practically relevant to form surface coatings. Herein, we systematically investigated the binding interactions between BSA proteins and different molar ratios of caprylic acid (CA), monocaprylin (MC), and methyl caprylate (ME) amphiphiles-all of which have 8-carbon-long, saturated hydrocarbon chains with distinct headgroups-and resulting effects on BSA adsorption behavior on silica surfaces. Our findings revealed that anionic CA had the greatest binding affinity to BSA, which translated into greater solution-phase conformational stability and reduced adsorption-related conformational changes along with relatively low packing densities in fabricated BSA adlayers. On the other hand, nonionic MC had moderate binding affinity to BSA and could stabilize BSA conformational properties in the solution and adsorbed states while also enabling BSA adlayers to form with higher packing densities. We discuss physicochemical factors that contribute to these performance differences, and our findings demonstrate how rational selection of amphiphile type and amount can enable control over BSA adlayer properties, which could lead to improved BSA protein-based surface coatings.

Preparation and BSA Adsorption Behavior of Chitosan-arginine Based Nanofiber Membranes

In this work, an affinity nanofiber membrane was successfully prepared by solution blowing of arginine-modified chitosan (CS-Arg) for bovine serum albumin (BSA) adsorption. CS-Arg was firstly synthesized by coupling L-arginine onto chitosan backbone. Then, CS-Arg nanofiber membranes (CANFs) were fabricated using solution blowing process with Polylactide (PLA) as assistant polymer. The results showed that CANFs effectively adsorbed BSA, and the adsorption capacities were influenced by the degrees of substitution (DS) of arginine in CS, pH value, contact time, and initial protein concentration. The highest adsorption capacity of 445.19 mg/g was achieved uvnder the following conditions: DS of 43.7 %, pH of 7.14, and initial concentration of 3.0 mg/ml. BSA adsorbed on the CANFs membrane conformed to Langmuir model, and the adsorption rate was consistent with the second-order kinetics model. This work implies that an arginine-modified chitosan nanofiber-based novel biomaterial has a potential application in adsorption of BSA.

Integration of mixed-mode chromatography and molecular imprinting technology for double recognition and selective separation of proteins

Abstract Adsorption selectivity is one of the most important parameters for chromatography. As a promising technology for protein purification, mixed-mode chromatography (MMC) has unique advantages; however, its selectivity needs to be improved further. In this study, one strategy for improving selectivity was tested. We combined MMC with molecular imprinting technology (MIT) to gain double-recognition capabilities. Molecularly imprinted polymer (MIP) enabled the enhancement of the selectivity of MMC. Cross-linked 4% agarose beads (4FF) with tryptamine (Try) as ligands were used to prepare the double-recognition resin (4FF-Try/MIPs), with bovine serum albumin (BSA) as the imprinting template protein. After removing the template protein from the imprinted layer, 3D cavities with double-recognition abilities toward BSA were obtained, owing to the combination of hydrophobic interaction and molecularly imprinted spatial matched cavities. The static and dynamic adsorption behaviors of BSA, bovine immunoglobulin G (bIgG), and bovine hemoglobin (BHb) on resins were investigated. The results showed 4FF-Try/MIPs retained the typical adsorption properties of pH dependence and salt tolerance of MMC. High and similar dynamic binding capacities for BSA were obtained for both 4FF-Try and 4FF-Try/MIPs. However, 4FF-Try/MIPs showed lower dynamic binding capacity for the competitive impurity bIgG. When 4FF-Try/MIPs was used to separate BSA from bovine serum, the purity reached 75.1%, which was higher than 4FF-Try by ∼20%. We conclude that MIT could be applied to enhance selectivity of MMC with double recognition capabilities, and this might be a straightforward strategy for improving selectivity in other modes of chromatography.

Probing Adsorption Behaviors of BSA onto Chiral Surfaces of Nanoparticles.

Chiral properties of nanoscale materials are of importance as they dominate interactions with proteins in physiological environments; however, they have rarely been investigated. In this study, a systematic investigation is conducted for the adsorption behaviors of bovine serum albumin (BSA) onto the chiral surfaces of gold nanoparticles (AuNPs), involving multiple techniques and molecular dynamic (MD) simulation. The adsorption of BSA onto both L- and D-chiral surfaces of AuNPs shows discernible differences involving thermodynamics, adsorption orientation, exposed charges, and affinity. As a powerful supplement, MD simulation provides a molecular-level understanding of protein adsorption onto nanochiral surfaces. Salt bridge interaction is proposed as a major driving force at protein-nanochiral interface interaction. The spatial distribution features of functional groups (COO- , NH3+ , and CH3 ) of chiral molecules on the nanosurface play a key role in the formation and location of salt bridges, which determine the BSA adsorption orientation and binding strength to chiral surfaces. Sequentially, BSA corona coated on nanochiral surfaces affects their uptake by cells. The results enhance the understanding of protein corona, which are important for biological effects of nanochirality in living organisms.

Reactive Maleimido Dextran Thin Films for Cysteine-Containing Surfaces Adsorbing BSA

The modification of surfaces by functional coatings or postmodification of films to control the adsorption of bovine serum albumin (BSA) is carried out. Surface functionalization with maleimido groups is achieved by spin coating of dextran derivatives. The layers are stabilized on the support material during thermal treatment or cross-linking. The thin films are characterized by atomic force microscopy, quartz crystal microbalance, FTIR spectroscopy, and X-ray photoelectron spectroscopy. Surface morphology, hydrophobicity, swelling behavior, and reactivity of dextran furfuryl carbamate bismaleimide adduct are suitable for the preparation of surfaces containing cysteine by thiol-ene reaction. The different functional surfaces obtained are investigated regarding their BSA adsorption behavior. Up to 9 mg m−2 of BSA are adsorbed on the nanorough, hydrophilized films at different pH values (4, 6, and 8.5) and thus a blocking layer can be obtained. The BSA layer may resist nonspecific adsorption of biological molecules and can be interesting for prevention of biofilm formation on medical devices.

Adsorption behavior of bovine serum albumin on Zn–Al and Mg–Al layered double hydroxides

In this work, non-calcined Mg–Al and Zn–Al layered double hydroxides (LDHs) with molar ratio of 3:1 were investigated for the adsorption of bovine serum albumin (BSA). Both LDHs were synthesized using the co-precipitation method and were characterized by X-ray diffraction, N2 adsorption–desorption isotherm at −196 °C, elemental analysis and X-ray photoelectron spectroscopy. The adsorption of BSA was evaluated in a batch adsorption system to assess the influence of buffer solution and buffer pH, contact time and initial concentration. Fixed-bed adsorption experiments were also performed in order to evaluate the dynamic adsorption behavior of BSA on the LDH as well as the regenerability of this material. In the batch adsorption experiments, the maximum amount of BSA adsorbed was reached at its isoelectric point (pI = 4.8) with 50 mM acetate buffer for Mg–Al LDH and pH 6.7 with 50 mM 2-(N-morpholino)ethanesulfonic acid (MES) buffer for Zn–Al LDH. The Langmuir and Langmuir–Freundlich models provided maximum equilibrium adsorption capacity of 338.74 and 346.54 mg g−1for Zn-Al LDH, respectively, and 196.12 and 197.80, respectively, for Mg-Al LDH. Column experiments were carried out with a constant flow of 1 mL min−1, varying the feed concentration of BSA solutions from 1.0 to 2.0 mg mL−1. An average of 98 % of BSA injected into the column was retained, and a completely elution was reached using 50 mM sodium phosphate with pH 12.

Protein nanoparticle interaction: A spectrophotometric approach for adsorption kinetics and binding studies

Investigating the protein nanoparticle interaction is crucial to understand how to control the biological interactions of nanoparticles. In this work, Model protein Bovine serum albumin (BSA) was used to evaluate the process of protein adsorption to the gold nanoparticles (GNPs) surface. The binding of a model protein (BSA) to GNPs was investigated through fluorescence quenching measurements. The strong affinities of BSA for GNPs were confirmed by the high value of binding constant (Ks) which was calculated to be 2.2 × 1011 L/mol. In this consequence, we also investigated the adsorption behavior of BSA on GNPs surface via UV–Vis spectroscopy. The effect of various operational parameters such as pH, contact time, initial BSA concentration, and temperature on adsorption of BSA was investigated using batch adsorption experiments. Kinetics of adsorption was found to follow the pseudo-second order rate equation. The suitability of Freundlich and Langmuir adsorption models to the equilibrium data was investigated. The equilibrium adsorption was well described by the Freundlich isotherm model. The maximum adsorption capacity for BSA adsorbed on GNPs was 58.71 mg/g and equilibrium constant was 0.0058 calculated by the Langmuir model at 298 K and pH = 11.0. Thermodynamic parameters showed that the adsorption of BSA onto GNPs was feasible, spontaneous, and exothermic.

Enhancement and Mitigation Mechanisms of Protein Fouling of Ultrafiltration Membranes under Different Ionic Strengths.

To determine further the enhancement and mitigation mechanisms of protein fouling, filtration experiments were carried out with polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes and bovine serum albumin (BSA) over a range of ionic strengths. The interaction forces, the adsorption behavior of BSA on the membrane surface, and the structure of the BSA adsorbed layers at corresponding ionic strengths were investigated. Results indicate that when the ionic strength increased from 0 to 1 mM, there was a decrease in the PVDF-BSA and BSA-BSA electrostatic repulsion forces, resulting in a higher deposition rate of BSA onto the membrane surface, and the formation of a denser BSA layer; consequently, membrane fouling was enhanced. However, at ionic strengths of 10 and 100 mM, membrane fouling and the BSA removal rate decreased significantly. This was mainly due to the increased hydration repulsion forces, which caused a decrease in the PVDF-BSA and BSA-BSA interaction forces accompanied by a decreased hydrodynamic radius and increased diffusion coefficient of BSA. Consequently, BSA passed more easily through the membrane and into permeate. There was less accumulation of BSA on the membrane surface. A more nonrigid and open structure BSA layer was formed on the membrane surface.

Salt and pH sensitive semi‐interpenetrating polyelectrolyte hydrogels poly(HEMA‐co‐METAC)/PEG and its BSA adsorption behavior

ABSTRACTA novel semi‐interpenetrating poly(2‐hydroxyethyl methacrylate) (pHEMA) based polyelectrolyte hydrogel [p(HEMA‐co‐METAC)/PEG] was prepared by copolymerizing HEMA with the cationic monomer 2‐methacryloyloxyethyltrimethyl ammonium chloride (METAC) in the presence of polyethylene glycol (PEG) with different content and molecular weight (MW 4000 and 400). The chemical structure of the gels was confirmed by FT‐IR spectroscopy, morphology study was performed by scanning electron microscope (SEM), thermal stability was revealed by thermogravimetric analysis (TGA), and the mechanical properties were determined by electronic universal testing machine. Swelling studies showed introduction of cationic monomer METAC led to high water content, and the obvious salt and pH sensitive properties were observed which proved the smart behavior of the semi‐interpenetrating polymer networks (IPNs) gels. In addition, the effect of temperature and some important biological solution on swelling behavior were reported. Cytotoxicity test demonstrated that synthesized gels owned satisfactory cytocompatibility and were convenient for the application as biomaterials. Finally, the weak bovine serum albumin (BSA) adsorption on semi‐IPNs by introducing METAC and controlling the content of PEG in gels demonstrated that they were of good protein resistance effect in biomedical applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41537.

Comparison between Kinetics Studies of Protein Adsorption by Single-walled Carbon Nanotube and Gold Nanoparticles Surfaces

In this research, a Bovine Serum Albumin (BSA) experiment was carried out and the produced BSA used to investigate the adsorption behavior of BSA from aqueous solutions by single-walled carbon nanotubes (SWCNTs) and Gold Nanoparticles (GNPs) through UV-Vis spectroscopy. The change of the parameter of contact time was tested in several adsorption experiments. The kinetic data indicate that the adsorption fits well with the pseudo first-order kinetic model for BSA adsorbed by GNPs and for SWCNTs was intraparticle diffusion model.

Adsorption of albumin by gold nanoparticles: Equilibrium and thermodynamics studies

In this research, bovine serum albumin (BSA) experiment was carried out and then the produced BSA was used to investigate the adsorption behavior of BSA from aqueous solutions through UV–Vis spectroscopy. The changes of parameters such as contact time, pH, BSA initial concentration and temperature were tested and investigated by several adsorption experiments. The equilibrium adsorption data were described as well and fitted better by the Freundlich adsorption isotherm than the four linear Langmuir models at all studied temperatures and pHs. Moreover, surface structural change was studied for the presence of BSA and gold nanoparticles (GNPs) before and after the experiment by FT-IR spectroscopy. The maximum adsorption capacity of BSA adsorbed by GNPs was 109.54mg/g and equilibrium constant was 0.0051 calculated by the Langmuir (four type) model at 298K and pH=8.6. The thermodynamic parameters implied that the adsorption processes were spontaneous and exothermic. The kinetic data indicate that the adsorption fits as well as with the pseudo first-order kinetic model.

Interaction of colloidal zinc oxide nanoparticles with bovine serum albumin and its adsorption isotherms and kinetics

Zinc oxide nanoparticles (ZnO NPs) are widely used in medical, industrial and household application owing to excellent antimicrobial property. The biocompatibility of nanoparticles is important for specific biomedical applications. The aim of this study was to stabilize and biofunctionalize ZnO NPs using bovine serum albumin (BSA). Here we have investigated the adsorption behavior of BSA onto ZnO NPs in aqueous solutions. Influence of pH on the adsorption of BSA onto ZnO NPs was also investigated. The study suggests that the electrostatic force of attraction favors the adsorption of BSA onto ZnO NPs. The adsorption data fitted well by Freundlich isotherm compared to Langmuir isotherm. The kinetics of adsorption fitted best to pseudo-second-order.

Towards understanding of protein adsorption behavior on plasma polymerized pyrrole film

Abstract Plasma polymerized pyrrole-like (PPpy) films exhibit good environmental stability and offer high reactivity with biomolecules. The present paper follows on from previous work on PPpy films applied as DNA immobilization/hybridization and describes the adsorption kinetics of bovine serum albumin (BSA) on PPpy films. Atom force microscopy was used to detect the surface roughness of PPpy surfaces obtained at different input powers or for different polymerization time, including the surface roughness before and after BSA adsorption. The influence of experimental conditions (i.e., the plasma input power, the polymerization time, the concentration of BSA, and the pH values of buffer solutions) on protein adsorption was investigated in situ by Surface plasmon resonance spectroscopy (SPR). SPR analysis confirmed the differently dynamic adsorption behavior of BSA on PPpy films under various experimental conditions. The adsorption constant, K a , was deduced from Langmuir isotherm equations, which were simulated using experimental data collected by SPR and electrochemical impedance spectroscopy (EIS). Analysis of the combination data of SPR and EIS indicates that PPpy films under various conditions show completely different adsorption behaviors and could be applied as biomaterials for electrochemical protein sensing or as protein-resistant.

Ion exchange membrane adsorption of bovine serum albumin—Impact of operating and buffer conditions on breakthrough curves

Abstract The relevant phenomena underlying the adsorption of proteins on ion exchange membranes with grafted polymer layers are not well understood yet. In this work the influence of operating and buffer conditions on the adsorption of bovine serum albumin (BSA) on anion and cation exchange membrane adsorbers is systematically investigated in order to find indications on the relevant mechanisms. The experimental results obtained at different buffer conditions are analyzed using the steric mass action model. Large differences were observed between the adsorption behavior of BSA on anion and cation exchange membranes. On the anion exchange membranes the dynamic binding capacity at 10% breakthrough was independent of the applied flow rate and decreased with increasing salt concentration. This in contrast to the cation exchange membranes, for which the dynamic binding capacity was strongly dependent on the flow rate and for which an optimum in binding capacity was observed at an intermediate salt concentration. Especially, the results obtained on cation exchange suggest a strong role of non-ideal effects such as steric hindrance and electrostatic repulsion in membrane adsorption. An improved understanding of these effects is required for further optimization of membrane adsorber materials.

Protein adsorption materials of the soluble conducting polymer poly(acryloyl chloride)-g-polypyrrole

In order to fabricate a soluble conducting polypyrrole matrix, applied as a biomaterial to anchor proteins, the preparation of a poly(acryoyl pyrrole)-g-polypyrrole (PAP-g-PPy) copolymer and the adsorption of bovine serum albumin (BSA) onto this conducting copolymer were studied. Polypyrrole (PPy) was synthesized by electrochemical polymerization on an Au surface, which had been spin-coated with a poly(acryloyl chloride) precursor containing a pyrrole moiety in its side chain. The chemical properties of PPy depend on the polymerization conditions, i.e., the concentration of pyrrole and the polymerization time. Subsequently, the adsorption behavior of BSA on PAP-g-PPy was investigated by surface plasmon resonance spectroscopy, suggesting that the copolymer thickness, the concentration of pyrrole monomer used in the preparation of the polymer, the BSA concentration and the pH value of buffer solutions can affect the adsorption behavior of BSA onto the polymer surface. It is therefore predicted that the conducting copolymer PAP-g-PPy could be used as an adsorbed matrix for protein adsorption.

A method for characterizing adsorption of flowing solutes to microfluidic device surfaces

We present a method for characterizing the adsorption of solutes in microfluidic devices that is sensitive to both long-lived and transient adsorption and can be applied to a variety of realistic device materials, designs, fabrication methods, and operational parameters. We have characterized the adsorption of two highly adsorbing molecules (FITC-labeled bovine serum albumin (BSA) and rhodamine B) and compared these results to two low adsorbing species of similar molecular weights (FITC-labeled dextran and fluorescein). We have also validated our method by demonstrating that two well-known non-fouling strategies [deposition of the polyethylene oxide (PEO)-like surface coating created by radio-frequency glow discharge plasma deposition (RF-GDPD) of tetraethylene glycol dimethyl ether (tetraglyme, CH(3)O(CH(2)CH(2)O)(4)CH(3)), and blocking with unlabeled BSA] eliminate the characteristic BSA adsorption behavior observed otherwise.

Formation, charged characteristic and BSA adsorption behavior of carboxymethyl chitosan/PES composite MF membrane

To improve charged characteristics of chitosan (CS), we have prepared an amphoteric chitosan derivative containing carboxylic acid (COOH) groups, i.e. N, O-carboxymethyl chitosan (CM-CS). The CM-CS is soluble in water over a wide pH range but is almost insoluble at its isoelectric point (IEP, pH 5.5). CM-CS/poly(ethersulfone) (PES) composite microfiltration (MF) membranes were prepared by immersing PES MF membranes into CM-CS solutions and cross-linking with glutaraldehyde. Streaming potential measurements indicate that the CM-CS/PES composite MF membranes possess weaker positively charged characteristic at low pH but stronger negatively charged characteristic at high pH than the chitosan composite membrane (CS/PES). It was further observed that the CM-CS/PES composite membranes have higher adsorption capacities of bovine serum albumin (BSA) than the CS/PES composite membrane and PES membrane at lower pH 3.0–4.7, and lower adsorption capacities at higher pH 6.0–8.0. Therefore, the CM-CS/PES composite membranes may resist protein fouling at high pH applications, and separate protein by adsorption at low pH applications.

Adsorption and Desorption of Serum Proteins Using Cellulosic Affinity Membrane Modified with N-Acetyl-l-phenylalanine

A cellulosic affinity membrane modified with N-acetyl-l-phenylalanine (N-Ac-l-Phe) was prepared intending to separate and purify the serum proteins. A porous cellulose membrane was first reacted with acrylonitrile to afford a cyanoethyl cellulose membrane (CEC membrane). After reduction of the cyano groups of the CEC membrane to obtain aminopropyl cellulose membrane (APC membrane), N-Ac-l-Phe was bound to the APC membrane through amide linkage (APC-Phe membrane). The pH dependence of the adsorption of serum proteins on the APC-Phe membrane was investigated in a dead-end flow mode, using bovine serum albumin (BSA) and γ-globulin (BγG) as model proteins. The adsorption behavior of BSA and BγG on the APC-Phe membrane was rather independent of pH, and the amount of BSA adsorbed on the membrane was greater than that of BγG. The BSA adsorbed on the APC-Phe membrane was recovered with hydroxycarboxylic acid solutions; whereas, it was not effectively eluted with NaCl solution.