Mixture Of Bovine Serum Albumin Research Articles

Micellization, interaction and thermodynamics behavior of BSA + SDS mixture in aqua-organic mixed solvent: Influences of temperature and solvent composition

The interaction of bovine serum albumin (BSA) with sodium dodecyl sulphate (SDS) in aqueous medium as well as aqua-organic mixed media has been performed using the conductivity measurement technique at several temperatures. The experiments were performed in the temperature ranges of 298.15–313.15 K with a gap of 5 K. The critical micelle concentration (CMC) and the degree of micelle ionization (α) have been computed from the specific conductivity versus the surfactant concentration plot. The CMC values achieved in the present study are dependent on the concentration of BSA, composition of the mixed solvent, and a variation of experimental temperature. For SDS + BSA mixture, an increase of BSA concentration causes a decrease in the values of CMC. Also, the values of CMC of SDS + BSA system in water-organic solvents were found to follow the order: CMCwater-DMF > CMCwater-AN > CMCwater-DMSO > CMCwater. In every case examined, the association of SDS + BSA mixture was spontaneous (negative ΔG0m). On the basis of observed ΔH0m and ΔS0m values for the SDS + BSA mixed system, it is expected that an electrostatic, hydrophobic, and ion–dipole interactions are in effect between SDS and BSA species, whereas the hydrophobic interaction is believed to be the main driving force for the aggregation process. In each of the case thoroughly detected, a linear relationship between ΔH0m and ΔS0m values was viewed, which is a strong indication in favor of the presence of enthalpy–entropy compensation phenomenon in the overall interaction process.

Exploring the interactions of acenaphthene with bovine serum albumin: Spectroscopic methods, molecular modeling and chemometric approaches

The interaction of acenaphthene (ACN), a widespread environmental pollutant, with bovine serum albumin (BSA) was explored using spectroscopic methods, molecular modeling and chemometric approaches. The multivariate curve resolution-alternating least squares (MCR-ALS) analysis decomposed the overlapped excitation-emission matrix (EEM) spectra of mixture of ACN and BSA successfully and extracted spectral profiles of pure BSA, ACN and BSA-ACN complex. Based on fluorescence quenching analysis, ACN quenched the inherent fluorescence of BSA remarkably via a static mechanism. The obtained value of binding constant (Kb = 3.82 × 105 L mol−1) revealed a high binding affinity of ACN to BSA which facilitates its distribution by blood circulation system. Furthermore, the binding parameters values revealed that one binding site in BSA was involved in BSA-ACN complex. FT-IR, UV–Vis and CD spectra showed that the conformation of BSA was altered in presence of ACN slightly. Molecular docking simulation suggested that ACN was located in the IA region of BSA and the main interactions between ACN and BSA, are van der Waals forces. The obtained results provide some insight into interactions between ACN and serum albumins at the molecular level.

Protein Adsorption on Core-shell Particles: Comparison of Capto™ Core 400 and 700 Resins

Structural and functional characteristics of the two core-shell resins Capto™ Core 400 and 700, which are useful for the flow-through purification of bioparticles such as viruses, viral vectors, and vaccines, are compared using bovine serum albumin (BSA) and thyroglobulin (Tg) as models for small and large protein contaminants. Both resins are agarose-based and contain an adsorbing core surrounded by an inert shell. Although shell thicknesses are comparable (3.6 and 4.2 µm for Capto Core 400 and 700, respectively), the two resins differ substantially in pore size (pore radii of 19 and 50 nm, respectively). Because of the smaller pores and higher surface area, the BSA binding capacity of Capto Core 400 is approximately double that of Capto Core 700. However, for the much larger Tg, the attainable capacity is substantially larger for Capto Core 700. Mass transfer in both resins is affected by diffusional resistances through the shell and within the adsorbing core. For BSA, core and shell effective pore diffusivities are about 0.25 × 10−7 and 0.6 × 10−7 cm2/s, respectively, for Capto Core 400, and about 1.6 × 10−7 and 2.6 × 10−7 cm2/s, respectively, for Capto Core 700. These values decrease dramatically for Tg to 0.022 × 10−7 and 0.088 × 10−7 cm2/s and to 0.13 × 10−7 and 0.59 × 10−7 cm2/s for Capto Core 400 and 700, respectively. Adsorbed Tg further hinders diffusion of BSA in both resins. Column measurements show that, despite the higher static capacity of Capto Core 400 for BSA, the dynamic binding capacity is greater for Capto Core 700 as a result of its faster kinetics. However, some of this advantage is lost if the feed is a mixture of BSA and Tg since, in this case, Tg binding leads to greater diffusional hindrance for BSA.

High Performance Countercurrent Membrane Purification for protein separations

Although pressure-driven membrane filtration is used extensively in bioprocessing, protein purification is currently performed by chromatographic separations due to the difficulty in achieving high selectivity for similarly sized species using commercially available ultrafiltration membranes in the absence of fouling. This work examines a novel approach for protein separations based on High Performance Countercurrent Membrane Purification (HPCMP), which exploits highly selective diffusive transport across the thin walls of a hollow fiber membrane. Experiments were performed using commercially available hemodialysis membranes using both polydisperse dextrans and a model protein mixture of bovine serum albumin (BSA) and myoglobin (Mb). Dextran transport data obtained using diffusive transport showed significantly greater selectivity than that for pressure-driven filtration. The HPCMP system was then used to separate BSA and Mb, achieving greater than 98% yield of both proteins with purification factors greater than 100-fold. The Mb product obtained in the draw (dialysate) solution had undetectable levels of BSA. Stable operation was achieved for 96 h without any evidence of membrane fouling due to the absence of any significant pressure-driven flow. These results demonstrate the feasibility of using HPCMP for high resolution separations in the preparation of biopharmaceuticals and natural protein products.

Membranes constructed by metal–ligand complexation for efficient phosphorus removal and fouling resistance in forward osmosis

Low permeation flux and rapid flux decline are challenging membrane technology in wastewater treatment. Here we used a metal–ligand complexation protocol to construct novel forward osmosis (FO) membrane for efficient and sustainable phosphorus removal. Disodium and tetrasodium salts of ethylenediaminetetraacetic acid (EDTA-2Na, EDTA-4Na) were separately grafted onto the conventional polyamide (PA) membranes via chemical complexation using Fe3+ as a bridge. These EDTA salts substantially improved the membrane properties. Consequently, the water fluxes produced by the EDTA-2Na and EDTA-4Na modified membranes increased by 109% (11.1 LMH) and 140% (12.7 LMH), respectively, relative to that of the pristine membrane (5.3 LMH) with 0.5 M NaCl as the draw solution. Meanwhile, the EDTA-4Na modified membrane surpassed the naked PA membrane in performance with higher water recovery efficiencies and solute rejections after long-term experiments against a mixture of bovine serum albumin and HPO42−. Moreover, the water flux recovery ratio of the naked PA membrane was only 51%, while that of the EDTA-4Na modified membrane reached over 93% after three cycles of fouling experiments. This study provides a new paradigm to develop FO membrane via a metal–ligand complexation protocol for efficient and sustainable wastewater treatment. Novel FO membranes synthesized through a complexation protocol are used for phosphorus removal and fouling resistance in forward osmosis.

Eggshell derived hydroxyapatite microspheres for chromatographic applications by a novel dissolution - precipitation method

Hydroxyapatite ((Ca10(PO4)6(OH)2, HAp) based chromatography matrix has attracted great interest in the field of protein separation. However, researchers have been trying to combat the growing costs associated with the HAp matrix. In the present investigation, we utilized a cheap biological waste material, viz. eggshells, for the development of hydroxyapatite (HAp) resins and evaluated them for protein purification. Initially, the calcite of the eggshell carbonate was converted into metastable vaterite microspheres. The HAp microspheres (ECHAp) were then prepared from eggshell carbonate microspheres using a novel dissolution-precipitation process. Synthetic source calcium carbonate was also used to prepare HAp microspheres (CHAp) for comparison. The purity and morphology of the apatite microspheres were characterized using X-ray diffraction (XRD) method, Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and laser diffraction particle analysis. Although both the apatites have similar morphology, the ECHAp has a larger surface area of 33.8 m2 g−1 compared to CHAp of 17.27 m2 g−1 by surface area analysis method. A commercial HAp matrix (CHT) with similar properties was also studied for comparison. All the apatite microspheres were found to have a similar protein binding capacity for bovine serum albumin (BSA). But ECHAp showed better protein separation for BSA and lysozyme mixture compared to CHAp and CHT matrices. The ECHAp matrix was also found to be highly stable over 20 purification cycles. Hence, the eggshell waste seems to have the potential for HAp matrix by a novel carbonate route with ease of preparation and also an economical packing material for chromatographic purification of biomolecules.

Molecular imprinting of bovine serum albumin and lysozyme within the matrix of polyampholyte hydrogels based on acrylamide, sodium salt of 2-acrylamido-2-methyl-1-propanesulfonic acid and (3-acrylamidopropyl)trimethyl ammonium chloride

Molecularly-imprinted polyampholyte (MIP) hydrogels based on nonionic monomer – acrylamide (AAm), anionic monomer – sodium salt of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and cationic monomer – (3-acrylamidopropyl)trimethyl ammonium chloride (APTAC) were obtained by immobilization of bovine serum albumin (BSA) and lysozyme in situ polymerization conditions. It was found that the best amphoteric hydrogel for sorption of BSA is APTAC-75H while for sorption of lysozyme is AMPS-75H. The sorption capacity of APTAC-75H and AMPS-75H with respect to BSA and lysozyme is 305.7 and 64.1-74.8 mg per 1 g of hydrogel respectively. Desorption of BSA and lysozyme from MIP template performed by aqueous solution of 1M NaCl is equal to 82-88%. Separation of BSA and lysozyme from their mixture was performed on MIP templates. The results of adsorption-desorption cycles of BSA on adjusted to BSA polyampholyte hydrogel APTAC-75H and of lysozyme on adjusted to lysozyme polyampholyte hydrogel AMPS-75H show that the mixture of BSA and lysozyme can be selectively separated with the help of MIP hydrogels.

Induction of Adipogenic Genes by Novel Serum-Free Conditions From Pre-adipocyte 3T3-L1 and ST2 Cells.

IntroductionObesity, defined as a condition of excessive fat accumulation in adipose tissue, is a global epidemic implicated in a myriad of processes deleterious to human health. It has become one of the leading impediments to public health globally. The study of obesity necessitates adipocyte models, which commonly employ a medium enriched with adipogenic hormones and fetal bovine serum (FBS) to culture terminal adipocytes. In the current study, we developed a novel protocol for serum-free differentiation of 3T3-L1 and ST2 pre-adipocytes using media enriched with free fatty acids (FFA) and bovine serum albumin (BSA). Differentiation was characterized by measuring FFA uptake and changes in expression of adipogenic genes. The novel protocol was also compared against the existing serum-inclusive method.MethodsThe National Institutes of Health (NIH)-3T3-L1 and ST2 pre-adipocyte cells were maintained in Dulbecco's Modified Eagle Medium (DMEM) containing 10% calf serum and 1% penicillin-streptomycin and Roswell Park Memorial Institute Medium (RPMI) with 10% FBS and 1% penicillin-streptomycin mixture, respectively, at 37℃, 5% CO2 in a humidified atmosphere. Differentiation was induced using a mixture of 0.25 µM dexamethasone, 0.5 mM 3-isobutyl-1-methylxanthine (IBMX), 10 µg/mL insulin, or 1% insulin-transferrin-selenium (ITS). Cells were cultured in serum-free media containing DMEM with BSA (2.5%) and lipid mixture 1 (LM1 1%) as well as serum-inclusive media enriched with 10% FBS. Total RNA was extracted, and quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed using delta-delta Ct method, also known as the 2-∆∆Ct method. Ribosomal protein, large, P0 (RPLP0) was used as a house-keeping gene for quantitation of relative expressions.ResultsWe observed an increase in fatty acid accumulation relative to controls using Oil Red O neutral lipid staining and spectrophotometry. This result was consistent with the effects of the serum-inclusive method. Differentiation was further confirmed by increased gene expression of adipogenic transcription factors - peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα); adipogenic genes - fatty acid-binding protein 4 (FABP4/aP2) and fatty acid translocase (FAT/CD36); and the lipogenic gene - perilipin by using quantitative RT-PCR.ConclusionOur data suggest that serum-free differentiation can significantly enhance the free fatty acid accumulation as well as adipogenic gene expression in both NIH-3T3-L1 and ST2 pre-adipocyte cells. Given the shortcomings of FBS, this method may provide advantages to the serum-inclusive protocols described previously.

Interaction of tetradecyltrimethylammonium bromide with bovine serum albumin in different compositions: Effect of temperatures and electrolytes/urea

Herein, the interaction of a protein, bovine serum albumin (BSA), with tetradecyltrimethylammonium bromide (TTAB, a cationic surfactant), has been investigated using the conductivity measurement technique in pure water and some sodium salts (NaCl, Na2SO4, Na2CO3, and Na3PO4) solutions at temperature range of 295.15–320.15 K. Results reveal that, in the plot of specific conductivity versus the concentration of TTAB, only a single critical micelle concentration (cmc) was found for the TTAB + BSA mixed system in all solvents media studied. The addition of BSA in aqueous TTAB solution, the value of cmc undergoes a change from its pure form, which indicates the presence of strong interaction operating between the BSA and TTAB molecules. In aqueous system, the cmc values of the TTAB + BSA mixtures are obtained higher compared to the values found for single TTAB surfactant. However, the addition of salt decreases the cmc value of mixed TTAB + BSA system. The values of cmc of the BSA + TTAB mixed system at 310.15 K and 1.00 mmol·kg−1 ionic strength of salt followed the order: cmcNa2CO3 > cmcNa3PO4 > cmcNaCl > cmcNa2SO4. The cmc values of TTAB + BSA mixture were found to be lowered in urea solution within the concentrations studied. The values of degree of dissociation (α) and fraction of counter ion binding (β) were found to be dependent on additives and temperature. The free energy of micellization (∆ Gmo) is negative for all the systems, which manifests that the micellization phenomenon is energetically spontaneous. The enhancement of the negative value of ∆ Gmo in aqueous salt solutions reveals an increase of spontaneity of the TTAB + BSA micellization process. The values of ∆ Gmo also reveal that the spontaneity of micelle formation is enhanced at higher temperatures in all media studied. The values of free energy of transfer (∆ Gm, to) were also determined for numerous solvent media used in the present study and described with appropriate reasoning.

Non-Enzymatic Protein Acetylation by 7-Acetoxy-4-Methylcoumarin: Implications in Protein Biochemistry.

The semi-synthetic acetoxycoumarins are known to acetylate proteins using novel enzymatic Calreticulin Transacetylase (CRTAase) system in cells. However, the nonenzymatic protein acetylation by polyphenolic acetates is not known. To investigate the ability of 7-acetoxy-4-methyl coumarin (7-AMC) to acetylate proteins non-enzymatically in the test tube. We incubated 7-AMC with BSA and analyzed the protein acetylation using Western blot technique. Further, BSA induced biophysical changes in the spectroscopic properties of 7-AMC was analyzed using Fluorescence spectroscopy. Using pan anti-acetyl lysine antibody, herein we demonstrate that 7-AMC acetylates Bovine Serum Albumin (BSA) in time and concentration dependent manner in the absence of any enzyme. 7-AMC is a relatively less fluorescent molecule compared to the parental compound, 7- hydroxy-4-methylcoumarin (7-HMC), however the fluorescence of 7-AMC increased by two fold on incubation with BSA, depending on the time of incubation and concentration of BSA. Analysis of the reaction mixture of 7-AMC and BSA after filtration revealed that the increased fluorescence is associated with the compound of lower molecular weight in the filtrate and not residual BSA, suggesting that the less fluorescent 7-AMC undergoes self-hydrolysis in the presence of protein to give highly fluorescent parental molecule 7-HMC and acetate ion in polar solvent (phosphate buffered saline, PBS). The protein augmented conversion of 7-AMC to 7-HMC was found to be linearly related to the protein concentration. Thus protein acetylation induced by 7-AMC could also be non-enzymatic in nature and this molecule can be exploited for quantification of proteins.

Biofilm modelling on the contact lenses and comparison of the in vitro activities of multipurpose lens solutions and antibiotics.

During the contact lens (CL) usage, microbial adhesion and biofilm formation are crucial threats for eye health due to the development of mature biofilms on CL surfaces associated with serious eye infections such as keratitis. For CL related eye infections, multi drug resistant Pseudomonas aeruginosa or Staphylococcus aureus (especially MRSA) and Candida albicans are the most common infectious bacteria and yeast, respectively. In this study, CL biofilm models were created by comparing them to reveal the differences on specific conditions. Then the anti-biofilm activities of some commercially available multipurpose CL solutions (MPSs) and antibiotic eye drops against mature biofilms of S. aureus, P. aeruginosa, and C. albicans standard and clinical strains were determined by the time killing curve (TKC) method at 6, 24 and 48 h. According to the biofilm formation models, the optimal biofilms occurred in a mixture of bovine serum albumin (20% v/v) and lysozyme (2 g/L) diluted in PBS at 37 °C for 24 h, without shaking. When we compared the CL types under the same conditions, the strongest biofilms according to their cell density, were formed on Pure Vision ≥ Softens 38 > Acuve 2 ∼ Softens Toric CLs. When we compared the used CLs with the new ones, a significant increase at the density of biofilms on the used CLs was observed. The most active MPS against P. aeruginosa and S. aureus biofilms at 24 h was Opti-Free followed by Bio-True and Renu according to the TKC analyses. In addition, the most active MPS against C. albicans was Renu followed by Opti-Free and Bio-True at 48 h. None of the MPSs showed 3 Log bactericidal/fungicidal activity, except for Opti-Free against S. aureus and P. aeruginosa biofilms during 6 h contact time. Moreover, all studied antibiotic eye drops were active against S. aureus and P. aeruginosa biofilms on CLs at 6 h and 24 h either directly or as 1/10 concentration, respectively. According to the results of the study, anti-biofilm activities of MPSs have changed depending on the chemical ingredients and contact times of MPSs, the type of infectious agent, and especially the CL type and usage time.

Influences of Combined Organic Fouling and Inorganic Scaling on Flux and Fouling Behaviors in Forward Osmosis

This study investigated the influence of combined organic fouling and inorganic scaling on the flux and fouling behaviors of thin-film composite (TFC) forward osmosis (FO) membranes. Two organic macromolecules, namely, bovine serum albumin (BSA) and sodium alginate (SA), and gypsum (GS), as an inorganic scaling agent, were selected as model foulants. It was found that GS scaling alone caused the most severe flux decline. When a mixture of organic and inorganic foulants was employed, the flux decline was retarded, compared with when the filtration was performed with only the inorganic scaling agent (GS). The early onset of the conditioning layer formation, which was due to the organics, was probably the underlying mechanism for this inhibitory phenomenon, which had suppressed the deposition and growth of the GS crystals. Although the combined fouling resulted in less flux decline, compared with GS scaling alone, the concoction of SA and GS resulted in more fouling and flux decline, compared with the mixture of BSA and GS. This was because of the carboxyl acidity of the alginate, which attracted calcium ions and formed an intermolecular bridge.

Facile synthesis of hydrophilic magnetic graphene nanocomposites via dopamine self-polymerization and Michael addition for selective enrichment of N-linked glycopeptides

The development of methods to effectively capture N-glycopeptides from the complex biological samples is crucial to N-glycoproteome profiling. Herein, the hydrophilic chitosan–functionalized magnetic graphene nanocomposites (denoted as Fe3O4-GO@PDA-Chitosan) were designed and synthesized via a simple two-step modification (dopamine self-polymerization and Michael addition). The Fe3O4-GO@PDA-Chitosan nanocomposites exhibited good performances with low detection limit (0.4 fmol·μL−1), good selectivity (mixture of bovine serum albumin and horseradish peroxidase tryptic digests at a molar ration of 10:1), good repeatability (4 times), high binding capacity (75 mg·g−1). Moreover, Fe3O4-GO@PDA-Chitosan nanocomposites were further utilized to selectively enrich glycopeptides from human renal mesangial cell (HRMC, 200 μg) tryptic digest, and 393 N-linked glycopeptides, representing 195 different glycoproteins and 458 glycosylation sites were identified. This study provides a feasible strategy for the surface functionalized novel materials for isolation and enrichment of N-glycopeptides.

Prototyping of a Microfluidic Modulator Chip and Its Application in Heart-Cut Strong-Cation-Exchange-Reversed-Phase Liquid Chromatography Coupled to Nanoelectrospray Mass Spectrometry for Targeted Proteomics.

A novel multilayer modulator chip offering a robust miniaturized interface for multidimensional liquid chromatography has been developed. The thermoplastic microfluidic device comprises five tailor-made functional layers, and the chip is compatible with commercially available switching-valve technology. The modulator chip allows for robust ultrahigh-pressure operation up to 65 MPa. Peak-dispersion characteristics of system peaks were assessed directly at the valve outlet by monitoring fluorescein injection profiles with laser-induced fluorescence detection. Integration of a microporous monolithic mixing entity in the microchannels significantly narrows the resulting peak profile. Proof-of-concept of the applicability of the microfluidic modulator chip is demonstrated in a heart-cut multidimensional strong-cation-exchange-reversed-phase liquid chromatography proteomics analysis workflow coupled to nanoelectrospray mass spectrometry for the target analysis of Glu-1-Fibrinopeptide B spiked in a protein digest mixture of bovine serum albumin.

Evaluation the binding of chelerythrine, a potentially harmful toxin, with bovine serum albumin

Chelerythrine (CHE), a benzophenanthridine alkaloid, is usually used as a nutritional and functional additive in variety of health foods. However, it should be paid enough attention because of its potential toxicity to human health. In this work, the binding mechanism of CHE with bovine serum albumin (BSA) was systematically investigated with spectroscopic approaches. The results showed that the mixture of BSA with CHE could spontaneously cause the formation of BSA-CHE complex through electrostatic interaction under simulative physiological conditions (0.01 mol L−1 Tris-HCl, 0.015 mol L−1 NaCl, pH = 7.4). Site marker competitive displacement experiments exhibited that CHE was primarily bound to the hydrophobic pocket of the site II (subdomain IIIA) of BSA. It has been reported that the binding of small functional molecules to serum albumins remarkably impacts their absorption, distribution, metabolism, conformation, and excretion features. Therefore, this study might be helpful for human to have an in-depth understanding of the biological effect of CHE in vivo and guide human to take it safely and reasonably.

Exploration of the binding between ellagic acid, a potentially risky food additive, and bovine serum albumin

Ellagic acid (EA), a natural plant polyphenol, is usually used as a functional additive in variety of health foods. However, the potential toxicity of EA to human health should be paid enough attention. To clarify its biological toxicity in vivo, this study explored the binding mechanism of EA with bovine serum albumin (BSA) by means of spectroscopic approaches and molecular docking insimulative physiological conditions. The results showed that the mixture of BSA with EA could spontaneously cause the formation of BSA-EA complex through electrostatic interaction under simulative physiological conditions (0.01 mol·L−1Tris-HCl, 0.015 mol L−1 NaCl, pH = 7.4). Molecular docking experiments revealed that EA was primarily bound to the hydrophobic pocket of the site I (subdomain IIA) of BSA. It has been reported that the binding of small functional molecules to serum albumins remarkably impacts their absorption, distribution, metabolism, and excretion features. Therefore, this study might be helpful for human to have an in-depth understanding of the biological effect of EA in vivo and guide human to take it safely and reasonably.

Effects of Adsorption of Albumin and Gamma-Globulin on the Tribological Performance of a Diamond-Like Carbon Film

The effects of surface adsorption of bovine serum albumin (BSA) and human gamma-globulin (HGG) on the tribological performance of a DLC film were investigated using a quartz crystal microbalance with dissipation (QCM-D), a ball-on-disk reciprocating tribometer, and a three-electrode electrochemical cell. The results showed that the wear depth in the BSA solution was higher than that in the HGG solution. In the HGG solution, the HGG-adsorbed layer could act as a lubricating layer and protect the DLC film from wear. The wear volume of DLC film in BSA and HGG mixture solution was higher than that in single HGG solution. This may be because the BSA molecules inhibit the formation of HGG adsorbed layer during sliding.

Coupled retention of bovine serum albumin and NOM by porous membranes

Coupled retention of natural organic matter (NOM) is an important process in membrane water treatment. A mechanistic understanding is lacking due to the complex nature of NOM. In this study, filtration experiments were conducted with the mixture of bovine serum albumin (BSA) and Suwannee River NOM (SRNOM) through different pore-sized membranes. A macroscopic depth filtration theory was utilized for analyzing the underlying mechanisms. The results showed the importance of BSA-SRNOM interactions on NOM retention. At a neutral pH of 7.0, the co-existing SRNOM reduced BSA retention by up to 24% by mitigating concentration polarization and inner-pore BSA deposition. Meanwhile, the presence of BSA elevated SRNOM retention by up to 23% because of SRNOM adsorption onto the deposited BSA, as well as enhanced steric hindrance and concentration polarization effect. Furthermore, the reduction of solution pH to 3.7 enhanced BSA-SRNOM interactions that favored multilayer BSA/SRNOM deposition. As a result, BSA and SRNOM retention increased by 54% and 79%, 78% and 37%, and 48% and 10% for membranes having pore radii of 7.5 nm, 15 nm and 25 nm, respectively. This study demonstrated that the interplay of concentration polarization, steric hindrance, and inner-pore deposition governed NOM retention by porous membranes.

Self-assembled polyelectrolyte complex nanoparticles as a potential carrier in protein delivery systems

BSA as a protein model was encapsulated in the alginate-based self-assembled polyelectrolyte complex nanoparticles using two distinct approaches. In the first approach, a mixture of bovine serum albumin (BSA) and alginate (ALG) solutions was added to the synthesized poly(2-(acryloyloxyethyl) trimethylammonium chloride) p(AETMACl) cationic polyelectrolyte, and the resulting polyelectrolyte complex was named as p(AETMACl)@BSA/ALG. In the second approach, the mixture of BSA and Ca2+ was added to the ALG solution. The pre-gel was formed rapidly through physical crosslinking followed by complexing with p(AETMACl) cationic polyelectrolyte and named as p(AETMACl)@BSA/ALG-Ca2+. To achieve the maximum encapsulation efficiency (EE%) for BSA, the interactions between different polymeric pairs including BSA/ALG, p(AETMACl)/BSA, and p(AETMACl)/ALG have been studied by UV–Vis spectroscopy. Maximum EE% of BSA was obtained around 100% for both approaches. Analyzing the BSA circular dichroism spectra showed a similar α-helical secondary structure for both free and released BSA after 24 h. The presence of Ca2+ in the formulations led to a decrease in the particle size from 400 to 300 nm for p(AETMACl)@ALG-Ca2+, and 1 μm to 800 nm for p(AETMACl)@BSA/ALG-Ca2+. Analyzing the release results from the Korsmeyer-Peppas kinetic model showed that the release mechanism of BSA was non-Fickian with calcium and Fickian without calcium.

The Influence of Albumin/glutaraldehyde Sealant in Early Results After Acute Type A Aortic Dissection

Mortality after acute type A aortic dissection (AAAD) is some of the highest in cardiac surgery. The dissected tissues are fragile and provide a thin layer for performing the aortic anastomoses. We study the influence of a mixture of bovine serum albumin (45%, w/v) and glutaraldehyde (10%, w/v) in a 4:1 ratio on bleeding and early results ([30 days) after AAAD repair.