Adsorption Of Bovine Serum Albumin Research Articles

Evaluation of the long-term antibiofilm effect of a surface coating with dual functionality of antibacterial and protein-repellent effects.

The provision of antibacterial properties to resinous restorative/reconstructive materials by incorporating polymerizable bactericides such as 12-methacryloyloxydodecylpyridinium bromide (MDPB) has been attempted. Previously, MDPB was combined with 2-methacryloyloxyethyl phosphorylcholine (MPC) to fabricate a copolymer coating to increase antibacterial effectiveness by protein repelling. In this study, we assessed the longevity of the protein-repelling, antibacterial, and antibiofilm effects of the MDPB-MPC copolymer. After 28 days of water immersion, MPC-containing copolymers exhibited lower adsorption of bovine serum albumin and salivary proteins; after 24 h of incubation, MDPB-containing copolymers demonstrated antibacterial effects against Streptococcus mutans. The copolymer containing both MDPB and MPC showed thinner biofilm formation with a higher percentage of membrane-compromised bacteria than control. The results were consistent with those before aging, indicating the long-lasting antibacterial, protein-repellent, and antibiofilm effects of this copolymer. The durable copolymer developed in this study can be applied to dental resins to control bacteria in the oral environment.

Electrochemical and physicochemical studies for adsorption of Bovine serum albumin for corrosion mitigation of zinc

Work deliberated here intended to study protection of sulfamic acid (NH2SO3H) induced corrosion of zinc using a biopolymer Bovine serum albumin (BSA). The efficacy of BSA was studied by potentiodynamic polarization measurements (PDP) and electrochemical impedance spectroscopy (EIS). Experimental parameters like concentration of NH2SO3H (0.1 M and 0.25 M), BSA (0.05–0.25 gL-1) and temperature (303 K–323 K) were varied to achieve maximum inhibition efficiency. Various adsorption isotherm models were tried and tested to understand the mode of adsorption. Adsorption of BSA was reaffirmed by surface (SEM, EDX, AFM) and spectroscopic (UV–Visible, AAS, FT-IR) studies. The inhibition efficiency increased with increased temperature, inhibitor concentration and acid concentration. A maximum of 89.1% inhibition efficiency was achieved at the concentration of 0.25 gL-1 BSA at 323 K in 0.25 M NH2SO3H. Thermodynamic calculations revealed the possibility of both physical and chemical adsorption of BSA on zinc. A suitable mechanism was predicted for the corrosion and inhibition process. BSA emerged as an excellent green inhibitor.

Mussel primed grafted zwitterionic phosphorylcholine based superhydrophilic/underwater superoleophobic antifouling membranes for oil-water separation

One of the most successful methods for reducing membrane fouling in filtration and separation applications is zwitterionic surface modification. Herein, poly[(2-methacryloyloxyethyl phosphorylcholine)-co-(glycidyl methacrylate)] (poly(MPC-co-GMA)) was synthesized as a zwitterionic polymer and grafted onto the polysulfone (PSF) microfilter membrane using polydopamine chemistry. The stepwise modifications and formation of the zwitterionic PgEDgMG membrane were established by analyzing chemical structure, surface morphology, charge, and wetting properties. The antifouling properties were established by bovine serum albumin (BSA) protein adsorption as low as 3.71 ± 0.78 µg cm−2, fluorescence imaging, and in-situ BSA adsorption via zeta potential measurements. After zwitterionization, the in-air and underwater oil wetting tests demonstrate the formation of superhydrophilic and superoleophobic membranes, which are critical for oil-water separation. Finally, the prepared membranes were evaluated in batch and continuous mode for soybean and silicone oil-water emulsion separation. The modified membrane demonstrated nearly complete oil rejection (>99%) and flux recovery up to 99% after a continuous 10-cycle operation along with retention of initial flux during continuous filtration for 12 h. Overall, the combination of polydopamine and poly(MPC-co-GMA) created a robust zwitterionic antifouling surface which induces superhydrophilic character and can be used for long-term water purification and sep-aration applications.

Tannic acid modified iron oxide nanoparticles and its application in protein adsorption: isotherm, kinetic, and thermodynamic study

Iron oxide nanoparticles, such as Fe3O4, are commonly used in various applications, such as drug delivery, magnetic fluid, water purification, and enzyme immobilization. These applications require protein to be adsorbed on the surface of iron oxide nanoparticles. However direct utilization of iron oxide nanoparticles has several drawbacks, thus modification of iron oxide nanoparticles is usually done. In this study, we reported surface modification of Fe3O4 using tannic acid to adsorb bovine serum albumin (BSA). The effect of modification and the BSA adsorption on the Fe3O4 was characterized using Fourier Transform Infrared Spectroscopy, X-ray Diffraction, Scanning Electron Microscopy, and Transmission Electron Microscopy. Furthermore the adsorption performance of modified and unmodified Fe3O4 was investigated at various initial pH, BSA concentration, and adsorption temperature. Several kinetic and isotherm adsorption models were used to describe the adsorption in this study. It was found that highest BSA adsorption was obtained at pH 4.8, near BSA’s isoelectric point. The adsorption kinetics followed the pseudo 2nd order model and reached equilibrium after 210 min adsorption. Based on Langmuir monolayer adsorption capacity, it was found that tannic acid modified Fe3O4 had 5 times higher adsorption capacity (222 mg/g), compared to unmodified Fe3O4 (46 mg/g). Furthermore, from the thermodynamic study, it was suggested that the BSA adsorption was endothermic, spontaneous, and random in nature.

Protein Adsorption on Poly-3-hydroxybutyrate and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate): Adsorption Isotherms and Conformational Analysis of the Adsorbed Protein

The equilibrium adsorption of bovine serum albumin (BSA) on poly-3-hydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) surfaces was studied at different solution concentrations. The equilibrium adsorption data were fitted to the Langmuir and Freundlich adsorption models. The protein adsorption behaviour was further investigated by analysing the conformation of surface adsorbed BSA using Fourier transform infrared (FTIR) spectroscopy with an Attenuated Total Reflectance (ATR) apparatus. The results showed that the Freundlich isotherm is a better fit for the adsorption of BSA on PHB and PHBV surfaces, which can be explained by the significant conformational changes that BSA undergoes upon adsorption.

On the adsorption kinetics of bovine serum albumin at the air–water interface

The adsorption kinetics of bovine serum albumin (BSA) at an air–water interface was investigated by experimentally measuring and theoretically modeling the dynamic surface tension (ST) data. A pendant bubble tensiometer was utilized for two ST measurements: (i) the adsorption onto a freshly created bubble surface and (ii) the bubble expansion/compression at the latter stage. The dynamic ST data, during the early stage of BSA adsorption, were best-fitted with the short-time approximation equation (diffusion-control) and the non-asymptomatic short-time formalism [mixed-control, Moorkanikkara and Blankschtein, JCIS, 296, 442–457 (2006)]. The fitting showed that the non-asymptotic short-time formalism could well predict the dynamic ST data; thereby, implying that the adsorption of BSA onto a clean air–water interface was mixed-controlled. A new approach for estimating the maximum surface concentration (Γ∞) and the intermolecular interaction amongst the adsorbed BSA molecules (K) was trialed. The relaxation of ST during a surface expansion was best-fitted with the Langmuir/Frumkin equation of state. A reasonably good fitting between the dynamic ST data and the theoretical ST profiles indicated that this approach could be used to estimate the Γ∞ and K for BSA without requiring the equilibrium ST data.

The effect of organic ligand modification on protein corona formation of nanoscale metal organic frameworks

Nanoscale metal organic frameworks (NMOFs) have been widely reported in biomedical field for their unique porous structure and tunable multifunctionality. However, when administrated in vivo, the protein corona will be formed on the surface of NMOFs, significantly affecting their biodistribution, pharmacokinetics and drug release. Few studies paid attention to the protein corona formation process and its influencing factors of NMOFs. As a well-established strategy for altering structure features of NMOFs, the organic ligand modification may have effect on the protein corona formation process, which is to be investigated. In this study, the zirconium (Zr)-based UIO66 was chosen as model NMOFs, the organic ligand of which was modified with amino group (-NH2) or carboxyl group (-COOH) to synthesize UIO66-NH2 and UIO66-2COOH, respectively. Bovine serum albumin (BSA) was chosen as model protein to investigate the protein corona formation process of NMOFs. The current results showed that the -COOH modification remarkably enhanced the BSA adsorption on NMOFs while -NH2 slightly decreased the protein binding affinity. These differences may be ascribed to the two different dominate protein corona formation modes, i.e., surface coating mode and porous embedded mode. The protein corona formation did not affect the crystal phase of NMOFs but increased the content of α-helix of BSA. Ultimately, upon protein corona formation, the cellular uptake of NMOFs was significantly affected. We believe our study will provide a new research paradigm to the design and applications of NMOFs.

Impact of polysaccharide and protein interactions on membrane fouling: Particle deposition and layer formation

Membrane fouling, which limits the application of membrane bioreactors, has received considerable research attention in recent years. In this work, filtration modeling was performed in combination with surface plasmon resonance (SPR) analysis to investigate the membrane fouling mechanism. Sodium alginate (SA) and bovine serum albumin (BSA) were used to perform dead-end filtration on hydrophilic and hydrophobic poly (vinylidene fluoride) (PVDF) membranes. The initial foulant deposition and layer formation on membranes as well as the interaction between the BSA and SA were comprehensively analyzed. Results indicated that during SA filtration, initial fouling on hydrophilic membranes were primarily attributed to the particle–membrane interactions, while the fouling on the hydrophobic membrane were dominantly caused by the interactions among SA particles. The interaction between BSA and SA led to more severe membrane fouling and hydrophobic membrane was more sensitive to it, especially in the initial filtration process. The SPR results helped clarify the in-situ deposition behavior of BSA and SA particles on the PVDF surface. Compared to SA, BSA adsorbed faster on the PVDF membrane, and specific interactions played an essential role in BSA adsorption, whereas the deposition of SA on PVDF could be easily removed by shear force. Interactions between BSA and SA could alleviate the bonding between BSA and the PVDF membrane.

Zwitterionic microgel based anti(-bio)fouling smart membranes for tunable water filtration and molecular separation

Tunable gating polymeric nanostructured membrane with excellent water permeability and precise molecular separation is highly advantageous for smart nanofiltration application. Polymeric nanostructures such as microgels with functionalizable cross-linkable moieties can be an excellent choice to construct membranes with a thin separation layer, functionality, and tunable transport properties. In the present work, we prepared switchable anti(bio)fouling membranes using zwitterionically functionalized antibacterial thermoresponsive aqueous core-shell microgels with a thin separation layer for controlled filtration and separation applications. The microgels were synthesized using a one-step graft copolymerization of poly(N-isopropylacrylamide) and polyethyleneimine (PEI) followed by zwitterionization of free amine groups of PEI chains with 1,3-propane sultone. Microgel synthesis and zwitterionization were confirmed by spectroscopic and elemntal analysis. The obtained microgels were thoroughly characterized to analyze their thermoresponsive behavior, morphology, charge, and antibacterial properties. After that, characterizations were performed to elucidate the surface properties, water permeation, rejection, and flux recovery of the microgel membranes prepared by suction filtration over a track-etched support. It was observed that zwitterionic membrane provides better hydrophilicity, lower bovine serum albumin (BSA) adsorption, and desirable antimicrobial activity. The pure water permeability was directly related to the microgel layer thickness, applied pressure, and temperature of the feed solution. The novel nanostructured membrane leads to an excellent water permeance with a high gating ratio, high flux recovery rate with low irreversible fouling, better rejection for various dyes, and foulant. Most importantly, the long-term performance of the membrane is appreciable as the microgel layer remains intact and provides excellent separation up to a longer period. Owing to easy preparation and well control over thickness, the zwitterionic microgel membranes constitute unique and interactive membranes for various pressure-driven separation and purification applications.

Fabrication and Characterization of YAG:Ce<sup>3+</sup> Phosphor Powder-Contained Photonic Crystal for Optical Sensor

In this study, the YAG:Ce3+ phosphor powder was used to fabricate polymer-based photonic crystal (PhC) for obtaining an enhancement of the fluorescence intensity. For fabricating PhC, YAG:Ce3+ phosphor powder was dispersed into the photocurable polymer, and then the PhC structure was transferred by using nanoimprint lithography. The optical characterization was carried out by monitoring the fluorescence intensity using a blue LED (460 nm) as a light source. For the evaluation of usability for sensor application, fluorescence intensity changes due to the adsorption of bovine serum albumin (BSA) were carried out. As the amount of BSA molecules adsorbed on the PhC surface increased, a decrease in fluorescence intensity depending on the BSA concentration was observed. Based on these results, the YAG:Ce3+ phosphor powder contained photonic crystal has the potential for biosensor application.

Preparation and characterization of agarose-encapsulated ceramic hydroxyapatite particles for flow-through chromatography

ABSTRACT Composite adsorbents were prepared by encapsulating ceramic hydroxyapatite particles (CHT Type I) within inert agarose beads using an emulsion method as stationary phases for the removal of small protein and nucleic acid impurities from large proteins and bioparticles in a flow-through mode. The composite particles were prepared with 6% and 10% agarose and contain 35% and 25% (v/v) CHT, respectively, with effective pore radii of 15.1 and 8.8 nm. The functional properties were studied using yeast RNA, bovine serum albumin (BSA), thyroglobulin (Tg), IgM, and 30 and 50 nm silica nanoparticles (NP) as models. The RNA and BSA adsorption capacities are smaller than for unencapsulated CHT on a bead volume basis but comparable when normalized by the volume of CHT particles in the composite beads attaining values between 30 and 40 mg/mL. Confocal laser scanning microscopy shows that, while RNA and BSA have complete access to the encapsulated CHT particles, Tg, IgM, and the NPs are largely excluded. RNA and BSA breakthrough experiments in laboratory-scale columns at a 5-min residence time show RNA and BSA binding capacities comparable to those measured in a batch mode with either single component feeds or with feed mixtures containing 30 nm NPs.

BSA ADSORPTION, ANTIBIOFILM, AND ANTIBIOFOULING BEHAVIOR OF POLY (N-TERT-AMYLACRYLAMIDE- COACRYLAMIDE/AMPSNa) HYDROGELS

In this study, Poly (N-tert- amylacrylamide-co-Acrylamide/AMPSNa) hydrogels (HG37, HG38, HG39, and HG40) were prepared by free-radical copolymerization of N-tert-amyl acrylamide (NTA), acrylamide (AM), and 2- Acrylamido-2-methyl-1-propane sodium sulfonate (AMPSNa). The hydrogels were characterized using FTIR, XRD, SEM, and TGA. The adsorption of bovine serum albumin (BSA) was evaluated at various pH levels and with different amounts of AMPSNa. Protein adsorption was shown to vary depending on pH and the amount of ionic monomer present. The BSA adsorption was complemented with XRD, SEM, and TGA. The maximum protein adsorption was reported at a pH of 5.0 which is closer to that of IEP. When assessed in vitro, the hydrogels were found to be effective in reducing biofilm formation (MTP assay) by Staphylococcus aureus (IC50 -20.45 µg/mL) and Pseudomonas aeruginosa (IC50 - 46.64 µg/mL). These hydrogels inhibited the formation of zoospores of the marine alga Ulva Lactuca (47.41 percent), indicating antimarine fouling activity in vitro.

Asymmetrical ultrafiltration membranes based on polylactic acid for the removal of organic substances from wastewater

The continued use of non-biodegradable polymeric-based membranes for water purification has led to an unsustainable accumulation of waste at disposal, resulting in various environmental problems. In this study, eco-friendly asymmetric ultrafiltration (UF) membranes were fabricated from polylactic acid (PLA) with different polymer concentrations using the phase inversion method. The fabricated membranes were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), contact angle, porosity, and pore size analysis. Permeate flux and organic matter (bovine serum albumin (BSA)) rejection were evaluated using synthetic wastewater. The anti-fouling properties of PLA membranes were investigated through static adsorption and dynamic filtration of BSA. Furthermore, the performance of the best performing PLA membrane was evaluated via chemical oxygen demand (COD) rejection as well as membrane fouling using raw municipal wastewater obtained from a local wastewater treatment plant (WWTP) in Abu Dhabi (UAE). The results indicated that increasing the PLA concentration to 20 wt% improved BSA removal from synthetic and raw wastewaters by up to 92 and 89%, respectively, in addition to improving the membrane anti-fouling property. The post-filtration and after cleaning FT-IR spectra revealed high antifouling property with no detection of BSA peaks, SEM images confirmed the reduction in membrane's pore size as PLA concentration increased, resulting in enhancing the antifouling properties of the membranes. In conclusion, this study demonstrated that PLA-UF membranes could be a viable eco-friendly alternative to traditional crude oil-derived membranes.

Pilot-scale modification of polyethersulfone membrane with a size and charge selective nanocellulose layer

The utilisation of plant-derived nanoscale cellulosic materials (cellulose nanofibrils, CNF) in tailoring water purification membranes is constantly gaining interest in the context of green-functionalised membrane solutions. However, most of the existing approaches based on renewable and biobased materials suffer from the lack of efficient and scalable processing strategies. Here, we introduce a roll-to-roll membrane modification approach based on thin submicron nanocellulose coatings (400–800 nm) to manufacture anti-biofouling membranes with size and charge dependent selectivity using unit operations compatible with existing industrial lines. We turned a commercial polymeric polyethersulfone (PES) microfiltration membrane into highly hydrophilic and tight membrane structure by applying thin and water-durable cellulose nanofibril layers using cast or spray coating methods. Nanocellulose coated membranes exhibited water permeance values of 80 – 100 LMH/MPa with the highest rejection levels of > 90% for Cytochrome C. Furthermore, the nanocellulose layers were able to withstand relatively high filtration pressure levels of 1 MPa, indicating that the selected procedures to improve mechanical integrity i.e. polyethylene imine-based anchoring and acid induced CNF cross-linking were successful. The coated membranes with the thinnest nanocellulose layer exhibited a molecular weight cut-off (MWCO) of 2 kDa for negatively charged polystyrene sulfonate and 14 kDa for neutral dextrane indicating charge selective behaviour. It can be concluded that our nanocellulose coated PES membranes represent nanofiltration membranes and lower boundary of ultrafiltration membranes with clear anti-biofouling performance directly evidenced via systematic bovine serum albumin (BSA) adsorption investigations. Our approach paves the way towards tunable and sustainable water treatment technologies simultaneously opening space for novel biobased solutions in membrane sector.

Enhanced model protein adsorption of nanoparticulate hydroxyapatite thin films on silk sericin and fibroin surfaces

Hydroxyapatite coated metallic implants favorably combine the required biocompatibility with the mechanical properties. As an alternative to the industrial coating method of plasma spraying with inherently potential deleterious effects, sol-gel methods have attracted much attention. In this study, the effects of intermediate silk fibroin and silk sericin layers on the protein adsorption capacity of hydroxyapatite films formed by a particulate sol-gel method were determined experimentally. The preparation of the layered silk protein/hydroxyapatite structures on glass substrates, and the effects of the underlying silk proteins on the topography of the hydroxyapatite coatings were described. The topography of the hydroxyapatite layer fabricated on the silk sericin was such that the hydroxyapatite particles were oriented forming an oriented crystalline surface. The model protein (bovine serum albumin) adsorption increased to 2.62 µg/cm2 on the latter surface as compared to 1.37 µg/cm2 of hydroxyapatite on glass without an intermediate silk sericin layer.The BSA adsorption on glass (blank), glass/c-HAp, glass/m-HAp, glass/sericin/c-HAp, and glass/sericin/m-HAp substrates, reported as decrease in BSA concentration versus contact time.

Studies into interactions and interfacial characteristics between cellulose nanocrystals and bovine serum albumin

This study investigates the interactions between cellulose nanocrystals (CNCs) and bovine serum albumin (BSA) under different pH conditions. A multiscale technique was employed to characterize the CNCs and BSA at pH 7 and pH 3. ζ-Potential measurement and UV–vis spectroscopy demonstrated strong interactions between CNCs and BSA at pH 3, whereat they have opposite charges. Interfacial tensiometry showed a deficiency in the surface activity of the CNCs and indicated that BSA dominated the interface behavior in their complex. Quartz crystal microbalance with dissipation revealed that the sequential adsorption of BSA and CNCs produced viscoelastic bilayers at pH 3, and the mass adsorbed was ∼ 28 times that adsorbed at pH 7. Molecular dynamics simulations indicated that the key interactions between the two materials were produced between the hydrophobic CNC surface and the BSA domain IIA region. These results provide interesting insights into the design of complex food emulsions and fluid interfaces.

Guest-Induced Planar-Chiral Pillar[5]arene Surface for Selectively Adsorbing Protein Based on Host-Guest Chemistry.

In living systems, the adsorption of a protein on biointerfaces is a universal phenomenon, such as the specific binding of an antibody and antigen, which plays an important role in body growth and life maintenance. The exploration of a protein-selective adsorption on the biointerface is of great significance for understanding the life process and treatment in vitro. Herein, on the basis of biomimetic strategies, we fabricated a planar-chiral NH2-pillar[5]arene modified silicon surface (pR-/pS-NP5 surfaces) for a highly enantioselective adsorption of protein by taking advantage of the guest-induced planar chirality of pillar[5]arenes. Results from practical experiments and theoretical calculations show that the pR-NP5 surface possesses a high adsorption capacity and chiral selectivity for bovine serum albumin (BSA). Moreover, it was identified that the guest-induced chiral effect the generation and amplification of planar chirality, which was much beneficial for enhancing the interaction between planar-chiral pillar[5]arene host and BSA. The binding capacity of pR-NP5 and BSA is stronger than that of pS-NP5, thus promoting the chiral selective adsorption of BSA. This work affords a deeper understanding of the chiral influence of protein adsorption on biointerfaces and meanwhile provides a new perspective for chiral-sensing applications.

Mesoporous Silica Nanoparticles Functionalized with Amino Groups for Biomedical Applications.

The synthesis and characterization of amino‐functionalized mesoporous silica nanoparticles are presented following two different synthetic methods: co‐condensation and post‐synthesis grafting of 3‐aminopropyltriethoxysilane. The amino groups’ distribution on the mesoporous silica nanoparticles was evaluated considering the aggregation state of a grafted photosensitizer (Verteporfin) by using spectroscopic techniques. The homogeneous distribution of amino groups within the silica network is a key factor to avoid aggregation during further organic functionalization and to optimize the performance of functionalized silica nanoparticles in biomedical applications. In addition, the formation of a protein corona on the external surface of both bare and amino‐functionalized mesoporous silica was also investigated by adsorbing Bovine Serum Albumin (BSA) as a model protein. The adsorption of BSA was found to be favorable, reducing the aggregation phenomena for both bare and amino‐modified nanoparticles. Nevertheless, the dispersant effect of BSA was much more evident in the case of amino‐modified nanoparticles, which reached monodispersion after adsorption of the protein, thus suggesting that amino‐modified nanoparticles can benefit from protein corona formation for preventing severe aggregation in biological media.

A hydrophobic antifouling surface coating on bioprosthetic heart valves for enhanced antithrombogenicity.

Thrombosis is an important factor that causes the failure of artificial biological valves in addition to calcification and immune rejection. A hydrophobic antifouling surface can improve blood compatibility by reducing the absorption of protein. In this study, porcine pericardium was cross-linked with glycidyl methacrylate, and carbon-carbon double bonds were introduced. Then, fluoride monomer was added so that the pericardial surface would become hydrophobic and antifouling. Fluoride modification changed the hydrophilicity of the pericardium surface, and the surface water contact angle increased from 84° to 143°. Compared with unmodified pericardium, the adsorption of bovine serum albumin and fibrinogen decreased by 93.1% and 85%, respectively, and the anti-thrombogenicity was greatly enhanced.

Evaluation of the dilational modulus of protein films by pendant bubble tensiometry

A new approach for evaluating the dilational modulus of an adsorbed protein film was proposed in this study; wherein, the air-water interface of Bovine serum albumin (BSA) aqueous solution was not subjected to a forced perturbation. The approach involved: (i) monitoring the relaxations of surface tension (ST), surface area (SA), and ambient/solution temperature of aqueous bovine serum albumin (BSA) solution using a pendant bubble tensiometer and (ii) detecting the numerous minute and low-frequency interfacial perturbances in the SA and ST relaxations (resultant from the minute variations in ambient temperature) at the latter stages of BSA adsorption process. For these perturbances, their surface dilational rate (dlnA/dt) and rate of ST change (dγ/dt) were determined, and then the dilational modulus (E = dγ/dlnA) was obtained from the slope of the linear best-fit in the plot of dγ/dt vs dlnA/dt. Using this approach, the dilational modulus of the adsorbed BSA film at a concentration of 0.052 and 15 (10−10 mol/cm3) was found to be 43 and 30 mN/m, respectively.