Bovine Serum Albumin Aqueous Solution Research Articles

Enhancing filtration flux and antifouling performance of PVDF membrane constructed from semi-interpenetrating network and block copolymers

Organic fouling causes the filtration property and serve life decrease of the PVDF membrane and is the challenge for filtration applications. Therefore, it is an urgency desire to construct a PVDF membrane with good filtration and antifouling for researchers. To this end, a based PVDF and poly(N-isopropyl acrylamide)(PNIPA) semi-interpenetrating network polymer was synthesized and used as membrane matrix for preparing semi-interpenetrating network/block copolymers blend membrane. The membrane composition, structure and performance were systematically characterized and investigated by FTIR spectrum, XPS, SEM, contact angle instrument and the other experimental techniques etc. Results indicate that the prepared membrane contains PVDF, PNIPA and block copolymer poly(ethylene oxide)-b-poly(propylene oxide)-b- poly(ethylene oxide) (F127) components, shows a porous cross section comprising a thin top surface layer with small pores, a finger-shape lower layer and a sponge-shape pore bottom layer. When the membrane are used for the filtration of bovine serum albumin(BSA) in aqueous solution at 25 ℃, the rejection can exceed 95.0% at a high flux of 307 L/(m2·h·bar). Simply raising filtration temperature to 60 °C, the flux can reach 606 L/(m2·h·bar) while the rejection barely changes, significantly improving the filtration ability of the membrane. Furthermore, the flux can recover above 93% of the original value after a BSA filtration and a subsequent water washing. Undoubtedly, the prepared membrane displays great potential for filtering BSA aqueous solution and the reason can be ascribed to the synergy between PNIPA and F127 of the membrane.

Iterative evaluation of micellar and thermodynamic properties of 12-2-12 in 1 % BSA aqueous solution in the presence of organic solvents and temperature

Abstract The interactions between a gemini surfactant 12-2-12 and bovine serum albumin (BSA) have been studied in aqueous and mixed aqueous media by conductance measurements using the iterative method at different temperatures ranging from 298.15 K to 313.15 K with step size 5. The critical micellar concentration (CMC) as well as the degree of ionization for the micelles (α) have been evaluated and their variation with solvent type and temperature has been discussed. The error for conductivity measurements was calculated and found to be much smaller than for surface tension measurements using the platinum ring method. The CMC values for the mixture of 12-2-12 and BSA in aqueous solvent solutions follow the sequence: DMF > AN > DMSO > water. These values were further confirmed by surface tension studies. From the thermodynamic parameters, hydrophobic interactions were found to be the driving force for micellization. The existence of enthalpy-entropy compensation was established from the linear plot of ΔH° m and ΔS° m .

The effect of buffer concentration on the dynamic/equilibrium surface tension of bovine serum albumin solution

The effect of phosphate buffer (Na2HPO4 and NaH2PO4) concentration on the dynamic and equilibrium surface tension (ST) of bovine serum albumin (BSA) solutions was examined in this study. A pendant bubble tensiometer was utilized for measuring the ST relaxation of BSA solutions in varying buffer concentration (0, 0.01–300 mM). The data showed: (i) an initial increase in buffer concentration (Cbuff < 0.3 mM) resulted in a slower ST relaxation and a notable rise in the equilibrium ST; (ii) a further rise in buffer concentration (Cbuff > 0.3 mM) resulted in a faster ST relaxation and a progressive decrease in the equilibrium ST; and (iii) despite an increase in BSA concentration from 2 to 15 (10−10 mol/cm3), the dynamic ST of BSA solutions always relaxed the slowest at Cbuff = 0.3 mM. The equilibrium ST of BSA solutions in 10 and 44 mM buffer [C = 0.1–15 (10−10 mol/cm3)] was also obtained and the data confirmed the near-constant equilibrium ST of purely aqueous BSA solutions [Le et al., J.Mol.Liq (2022) 118305] to not be an anomalous behavior but, observable irrespective of the solvent formulation.

Adsorption of BSA Protein in Aqueous Medium Using Vegetable Tannin Resin from Acacia mearnsii (Mimosa) and Modified Lignocellulosic Fibers from the Bark of Eucalyptus citriodora.

Proteins are abundant biomolecules found in human cells, as well as pathogenic bacteria and viruses. Some of them become pollutants when released into water. Adsorption is an advantageous method for separating proteins in aqueous media since proteins are already immobilized on solid surfaces. Adsorbents with surfaces rich in tannins are efficient due to their affinity for strong interactions with the various amino acids that make up proteins. This work aimed to develop an adsorbent for protein adsorption in aqueous medium using lignocellulosic materials modified from eucalyptus bark and vegetable tannins. A more efficient resin was prepared containing 10% eucalyptus bark fibers and 90% tannin mimosa by condensation with formaldehyde, and it was characterized by UV–Vis, FTIR-ATR spectroscopy and determinations of degree of swelling, bulk and bulk density and specific mass. For UV–Vis spectroscopy the percentage of condensed and hydrolysable tannins in the extracts of fibers of the dry husks of Eucalyptus Citriodora was estimated and it was also determined your soluble solids. The study of bovine serum albumin (BSA) adsorption was carried out in batch with quantification by UV–Vis spectroscopy. The most efficient prepared resin obtained 71.6 ± 2.78% removal in a solution of 260 mg L−1 of BSA working in a better pH range of the aqueous solution of BSA in its isoelectric point, ~ 5, 32 ± 0.02, under these conditions, the synthesized resin can reach a maximum BSA adsorption capacity of ~ 26.7 ± 0.29 mg g−1 in 7 min. The new synthesized resin presents good prospects for adsorption of proteins or species that in their structure have higher percentages of amino functional groups or amino acids with aliphatic, acidic and/or basic hydrophilic characteristics.

Nanodroplet vaporization with pulsed-laser excitation repeatedly amplifies photoacoustic signals at low vaporization thresholds.

Nanodroplets' explosive vaporization triggered by absorption of laser pulses produces very large volume changes. These volume changes are two orders of magnitude higher than those of thermoelastic expansion generated by equivalent laser pulses, and should generate correspondingly higher photoacoustic waves (PAW). The generation of intense PAWs is desirable in photoacoustic tomography (PAT) to increase sensitivity. The biocompatibility and simplicity of nanodroplets obtained by sonication of perfluoropentane (PFP) in an aqueous solution of bovine serum albumin (BSA) containing a dye make them particularly appealing for use as contrast agents in clinical applications of PAT. Their usefulness depends on stability and reproducible vaporization of nanodroplets (liquid PFP inside) to microbubbles (gaseous PFP inside), and reversible condensation to nanodroplets. This work incorporates porphyrins with fluorinated chains and BSA labelled with fluorescent probes in PFP nanodroplets to investigate the structure and properties of such nanodroplets. Droplets prepared with average diameters in the 400-1000 nm range vaporize when exposed to nanosecond laser pulses with fluences above 3 mJ cm-2 and resist coalescence. The fluorinated chains are likely responsible for the low vaporization threshold, ∼2.5 mJ cm-2, which was obtained from the laser fluence dependence of the photoacoustic wave amplitudes. Only ca. 10% of the droplets incorporate fluorinated porphyrins. Nevertheless, PAWs generated with nanodroplets are ten times higher than those generated by aqueous BSA solutions containing an equivalent amount of porphyrin. Remarkably, successive laser pulses result in similar amplification, indicating that the microbubbles revert back to nanodroplets at a rate faster than the laser repetition rate (10 Hz). PFP nanodroplets are promising contrast agents for PAT and their performance increases with properly designed dyes.

Effect of Laser-Induced Optical Breakdown on the Structure of Bsa Molecules in Aqueous Solutions: An Optical Study.

The influence of laser radiation of a typical surgical laser on the physicochemical properties of the Bovine Serum Albumin (BSA) protein was studied. It was established that the physicochemical characteristics of optical breakdown weakly depend on the concentration of protein molecules. At the same time, the patterns observed for an aqueous solution of BSA irradiated with a laser for different time periods were extremely similar to the classical ones. It was established that after exposure to laser radiation, the optical density of protein solutions increases. At the same time, the intensity of BSA fluorescence due to aromatic amino acid residues decreases insignificantly after exposure to laser radiation. In this case, the position of the excitation and emission maximum does not change, and the shape of the fluorescence spot on 3D maps also does not change significantly. On the Raman spectrum after exposure to laser radiation, a significant decrease in 1570 cm−1 was observed, which indicates the degradation of α-helices and, as a result, partial denaturation of BSA molecules. Partial denaturation did not significantly change the total area of protein molecules, since the refractive index of solutions did not change significantly. However, in BSA solutions, after exposure to laser radiation, the viscosity increased, and the pseudoplasticity of aqueous solutions decreased. In this case, there was no massive damage to the polypeptide chain; on the contrary, when exposed to optical breakdown, intense aggregation was observed, while aggregates with a size of 400 nm or more appeared in the solution. Thus, under the action of optical breakdown induced by laser radiation in a BSA solution, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues are damaged to a lesser extent, and fragmentation of protein molecules is not observed.

On the equilibrium surface tension of aqueous protein solutions – Bovine serum albumin

The dynamic and equilibrium surface tension (ST) data of proteins such as bovine serum albumin (BSA) are crucial in numerous theoretical and practical applications. However, reliable equilibrium ST of BSA is absent in the literature. This study illustrates a more precise and accurate approach for measuring equilibrium ST of aqueous BSA solutions. The ST relaxation of aqueous BSA solution [C = 0.052–15 (10-10 mol/cm3)] was monitored using a pendant bubble tensiometer for 2–5 days, depending on the BSA concentration. The dynamic ST indicated that irrespective of the BSA concentration, the ST remained nearly constant at the latter stage for several tens of hours. These ST values were further confirmed by a perturbation process (a forced, rapid expansion/compression of the bubble surface).The data indicated that the equilibrium ST of BSA(aq) solutions remained essentially unchanged over a wide range of BSA concentration [C = 0.052 to 15 (10-10 mol/cm3)] at 51.5 ± 0.3 mN/m.

A novel method for fabrication of paper-based microfluidic devices using BSA-ink

This paper describes the fabrication of paper-based microfluidic devices using a novel, inexpensive ink composed of bovine serum albumin (BSA), utilizing BSA's thermal denaturation and aggregation to create a hydrophobic barrier on Whatman® Grade 4 filter paper. A 20% aqueous solution of BSA was inked onto the paper using a pen plotter at moderate speed (5 cm/s) with desired shape and size followed by heating at 80 °C to denature the BSA leading to hydrophobic barriers formation, whereas below 80 °C the barrier layer is prone to collapse. The minimum line gap and line width of ~1 mm and ~1.3 mm were achieved. Finally, a proof-of-concept glucose sensing was shown while addressing the issue of the coffee ring effect using the biopolymer NanoCheck-ATH® from ChitoLytic Inc. The glucose concentration limit of detection (LOD) as low as 0.2 mg/mL was estimated. The developed technique offers ease of fabrication, high reproducibility, cost-effectiveness, and is environmentally friendly.

Protein-assisted scalable mechanochemical exfoliation of few-layer biocompatible graphene nanosheets.

A facile method to produce few-layer graphene (FLG) nanosheets is developed using protein-assisted mechanical exfoliation. The predominant shear forces that are generated in a planetary ball mill facilitate the exfoliation of graphene layers from graphite flakes. The process employs a commonly known protein, bovine serum albumin (BSA), which not only acts as an effective exfoliation agent but also provides stability by preventing restacking of the graphene layers. The latter is demonstrated by the excellent long-term dispersibility of exfoliated graphene in an aqueous BSA solution, which exemplifies a common biological medium. The development of such potentially scalable and toxin-free methods is critical for producing cost-effective biocompatible graphene, enabling numerous possible biomedical and biological applications. A methodical study was performed to identify the effect of time and varying concentrations of BSA towards graphene exfoliation. The fabricated product has been characterized using Raman spectroscopy, powder X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The BSA-FLG dispersion was then placed in media containing Astrocyte cells to check for cytotoxicity. It was found that lower concentrations of BSA-FLG dispersion had only minute cytotoxic effects on the Astrocyte cells.

Aggregation Behavior of Poly(Acrylic acid-co-Octadecyl Methacrylate) and Bovine Serum Albumin in Aqueous Solutions.

Polymer‐protein complexing systems have been extensively studied because of their wide application in biomedicine and industry. Here, we studied the aggregation behavior of the hydrophobically associating water‐soluble polymer poly(acrylic acid‐co‐octadecyl methacrylate) [P(AA‐co‐OMA)] prepared with nonionic surfactant as an emulsifier and bovine serum albumin (BSA) in aqueous solution. We identified the optimal composite conditions of P(AA‐co‐OMA) and BSA aqueous solution. We measured the zeta potential, dynamic light‐scattering particle size, and surface tension of P(AA‐co‐OMA) and BSA mixed aqueous solution. The results showed that the aggregation behavior between the polymer and BSA relied mainly on the hydrophobic interactions between the molecules. In addition, the best compounding condition was 8 wt.% of P(AA‐co‐OMA) content. The structure of hydrophobically associating polymer P(AA‐co‐OMA) and its aggregation with BSA were characterized by Fourier‐transform infrared spectroscopy. The infrared spectroscopy results identified the hydrogen bonding behavior of the amino and carboxyl groups between the polymer and BSA. This behavior was also confirmed using thermogravimetric analysis and differential scanning calorimetry. The thermal decomposition temperature and melting temperature of BSA changed before and after it was combined with the polymer. We measured the morphology of the polymer BSA aggregate with 8 % polymer content by transmission electron microscopy. The binding mechanism was investigated, as well.

A combined interfacial polymerization and in-situ sol-gel strategy to construct composite nanofiltration membrane with improved pore size distribution and anti-protein-fouling property

Pore size distribution is crucial for the application of nanofiltration membrane in size-selective separation of industrial fluids. In this work, a novel combined interfacial polymerization (IP) and in-situ sol-gel strategy was proposed to fabricate composite nanofiltration membrane with narrow pore size distribution. Aqueous solution of piperazine and polyvinyl alcohol (PVA) was employed to perform interfacial polymerization with organic solution of trimesoyl chloride and tetraethyl orthosilicate (TEOS) on porous support. The non-reactive additive TEOS within the interfacially synthesized selective separation layer was then employed to perform sol-gel. The space-limited hydrolysis and condensation of TEOS molecules and their chemical bonding with PVA molecules were confirmed by analyzing membrane physico-chemical property and were found to be effective in tuning mean pore diameter, narrowing the pore size distribution and thus enhancing membrane perm-selectivity. Compared to those of membrane PA1 with similar mean pore size fabricated by only IP technique, the water permeability and rejection ratio of PEG1000 to raffinose (RPEG1000/Rraffinose) of membrane PA-TEOS0.5 fabricated by combined IP and sol-gel technique were higher by 25.0 and 20.1%, respectively. Moreover, static adsorption and dynamic deposition tests using aqueous bovine serum albumin solution proved that in-situ sol-gel process could endow the membrane with better protein fouling resistance.

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.

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.

Spectroscopic study of conformation changes of bovine serum albumin in aqueous environment

The secondary structural changes of bovine serum albumin (BSA) aqueous solutions with and without calcium cations were investigated by attenuated total reflection-Fourier transform infrared (ATR-FTIR) technology. The spectra of BSA solution and BSA dry powder were mainly reflected the formation of hydrogen bonds between water and BSA. Further investigation indicated that the concentrations of calcium cations in BSA aqueous solution also affected the secondary structural change of the protein. Amide I band was red shifted and amide II band was blue shifted in aqueous environment compared with the dry BSA powder, and the addition of calcium cations further changed the amide bands position, which led to the change of the secondary structure. The result was coinciding with the Raman spectroscopy.

Synergistic effect of carboxylated-MWCNTs on the performance of acrylic acid UV-grafted polyamide nanofiltration membranes

Surface modification of a commercial polyamide nanofiltration membrane was achieved by UV induced graft polymerization of acrylic acid and incorporation of carboxylated-MWCNTs (COOH-MWCNTs). The grafting process was done under different monomer concentrations and UV exposure times. The modified membranes were characterized through scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle and zeta-potential analysis, and cross-flow filtration experiments. Changes in the surface hydrophilicity, negative charge and roughness of the modified membranes improved their permeability and fouling resistance significantly. The membrane grafted with 50 g/L acrylic acid under 5 min UV exposure showed the best filtration performance including pure water flux of 38.8 L/m2 h, salt rejections of 97.43% (Na2SO4) and 93.4% (NaCl), and flux recovery ratio (FRR) of 80.2% during bovine serum albumin (BSA) filtration. After optimizing grafting condition, different amounts of COOH-MWCNTs were dispersed in the monomer solution for embedding in the grafting layer. By adding 0.2 wt% COOH-MWCNTs to the grafting layer, a water flux improvement of around 30% was observed. But, excess loading of the COOH-MWCNTs led to compaction of the grafting layer and made it inflexible and subsequently, reduced the hydrophilicity and permeability of the membrane. Fouling tests with BSA aqueous solution showed that antifouling ability of the modified membranes was remarkably improved at all concentrations of the COOH-MWCNTs. Furthermore, salt rejection results displayed that simultaneous surface modification through grafting and COOH-MWCNTs embedding could effectively improve the nanofiltration performance of the membranes in the term of permeability, desalination and fouling resistance.

Effect of Mussel‐Inspired Poly(Dopamine)‐Functionalized Carbon Nanotubes/Graphene Nanohybrids on Interfacial Adhesion of Soy Protein‐Based Nanocomposites

The demands for strong integrated biopolymer materials have substantially increased across various industries. In this study, a biomimic strategy was proposed to prepare the poly(dopamine)‐functionalized carbon nanotubes (PDCNTs) via mussel‐inspired chemistry. The graphene dispersion was prepared in aqueous bovine serum albumin solution by ultrasonic treatment through a facile and green approach. Inspired by the excellent integration of mechanical properties and hierarchical nano/microscale structure of natural nacre, we fabricated soy isolate protein (SPI)‐based nanocomposite film with 2D graphene nanosheets and 1D surface‐functionalized PDCNTs through a layer‐by‐layer assembly process. The morphology and thickness of graphene nanosheets were analyzed by atomic force microscopy. The successful surface modification of PDCNTs was confirmed by X‐ray photoelectron spectroscopy and transmission electron microscopy. The cross‐linking hierarchical structure of the SPI hybrid film was observed in scanning electron microscopy images. A combination of multiple interfacial interactions and enhanced adhesion between the PDCNTs‐graphene conjugation and SPI matrix resulted in a remarkable improvement in the mechanical properties of the SPI‐based nanocomposites. When compared with the unmodified film, the tensile strength and elongation at break of the hybrid film were simultaneously increased by 158.93 and 78.67%, respectively. As a result of the enhanced tortuosity effect, the water vapor permeability was significantly reduced by 33.65%. In addition, the resultant film also possessed favorable water resistance, thermal stability, and ultraviolet–visible light barrier behavior. This work provided a novel bio‐inspired interfacial toughening strategy for constructing high performance biopolymer nanocomposites. POLYM. COMPOS., 40:E1649–E1661, 2019. © 2018 Society of Plastics Engineers

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.

Interactions between Proteins and the Membrane Surface in Multiscale Modeling of Organic Fouling.

In the present paper, an improved multiscale modeling aimed at describing membrane fouling in the UltraFiltration (UF) process was proposed. Some of the authors of this work previously published a multiscale approach to simulate ultrafiltration of Bovine Serum Albumin (BSA) aqueous solutions. However, the noncovalent interactions between proteins and the membrane surface were not taken into account in the previous formulation. Herein, the proteins-surface interactions were accurately computed by first-principle-based calculations considering also the effect of pH. Both the effective surface of polysulfone (PSU) and the first layer of proteins adsorbed on the membrane surface were accurately modeled. Different from the previous work, the equilibrium distance between proteins was calculated and imposed as lower bound to the protein-protein distances in the compact deposit accumulated on the membrane surface. The computed BSA surface charges were used to estimate the protein potential and the charge density, both necessary to formulate a forces balance at microscopic scale. The protein surface potential was compared with Z-potential measurements of BSA aqueous solution, and a remarkable agreement was found. Finally, the overall additional resistance, as due to both the compact and loose layers of the deposit, was computed, thus allowing the final transition to a macroscopic scale, where an unsteady-state mass transfer model was formulated to describe the behavior of a typical dead-end UF process. A good agreement between simulated and experimental permeate flux decays was observed.

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.

BODIPY dyes in bio environment: Spectral characteristics and possibilities for practical application

Abstract Boron dipyrrin (BODIPY) dyes serve as perspective fluorescent sensors and probes in a vast range of biochemical and medical applications. Thus, mechanisms of interaction with biomolecules and accompanying spectral behavior of BODIPY are of major interest for fundamental science and practical applications. 8-aryl BODIPY derivatives were found to have high fluorescent respond upon the protein addition. Investigation of the interaction between the series of BODIPY complexes and Bovine Serum Albumin (BSA) using ultraviolet-visible (UV-vis) absorption, fluorescence spectroscopy under simulated physiological conditions (pH 7.4) and molecular docking methods was performed. The results of fluorescence spectroscopy indicated that the fluorescence of hydrophobic BODIPY dyes substantially increases in the presence of BSA. The prospected reason is binding of the dye to the BSA hydrophobic cavities in the subdomain IIA. Aromatic moiety size increase causes shifting of the interaction driving force from mostly non-specific to the π-stacking. Among all probes, the 8-phenyl substituted dye showed the highest sensitivity and the quantitative fluorescent response for BSA in aqueous solution. BODIPY with 8-phenyl substituent or analogs therefore could be used as protein surface polarity sensors, at the same time all of the investigated dyes with bulky aromatic groups could be used as hydrophobic molecule tags and markers for bioimaging tasks.