Presence Of Bovine Serum Albumin Research Articles

Photophysical Characterization and Biointeractions of NIR Squaraine Dyes for in Vitro and in Vivo Bioimaging.

The increasing demand for reliable near-infrared (NIR) probes exhibiting enduring fluorescence in living systems and facile compatibility with biomolecules such as peptides, antibodies or proteins is driven by the increasing use of NIR imaging in clinical diagnostics. To address this demand, a series of carboxy-functionalized unsymmetrical squaraine dyes (SQ-27, SQ-212, and SQ-215) along with non-carboxy-functionalized SQ-218 absorbing and emitting in the NIR wavelength range were designed and synthesized followed by photophysical characterization. This study focused on the impact of structural variations in the alkyl chain length, carboxy functionality positioning, and spacer chain length on dye aggregation and interaction with bovine serum albumin (BSA) as a model protein. In phosphate buffer (PB), the absorption intensity of the dyes markedly decreased accompanied by pronounced shoulders indicative of dye aggregation, and complete fluorescence quenching was seen in contrast to organic solvents. However, in the presence of BSA in PB, there was a enhancement in absorption intensity while regaining the fluorescence coupled with a remarkable increase in the intensity with increasing BSA concentrations, signifying the impact of dye-BSA interactions on preventing aggregation. Further analysis of Job's plot unveiled a 2:1 interaction ratio between BSA and all dyes, while the binding studies revealed a robust binding affinity (Ka) in the order of 107/mol. SQ-212 and SQ-215 were further tested for their in vitro and in vivo imaging capabilities. Notably, SQ-212 demonstrated nonpermeability to cells, while SQ-215 exhibited easy penetration and prominent cytoplasmic localization in in vitro studies. Injection of the dyes into laboratory mice showcased their efficacy in visualization, displaying stable and intense fluorescence in tissues without toxicity, organ damage, or behavioral changes. Thus, SQ-212 and SQ-215 are promising candidates for imaging applications, holding potential for noninvasive cellular and diagnostic imaging as well as biomarker detection when coupled with specific vectors in living systems.

Albumin Protein Impact on Early-Stage In Vitro Biodegradation of Magnesium Alloy (WE43).

Mg and its alloys are promising biodegradable materials for orthopedic implants and cardiovascular stents. The first interactions of protein molecules with Mg alloy surfaces have a substantial impact on their biocompatibility and biodegradation. We investigate the early-stage electrochemical, chemical, morphological, and electrical surface potential changes of alloy WE43 in either 154 mM NaCl or Hanks' simulated physiological solutions in the absence or presence of bovine serum albumin (BSA) protein. WE43 had the lowest electrochemical current noise (ECN) fluctuations, the highest noise resistance (Zn = 1774 Ω·cm2), and the highest total impedance (|Z| = 332 Ω·cm2) when immersed for 30 min in Hanks' solution. The highest ECN, lowest Zn (1430 Ω·cm2), and |Z| (49 Ω·cm2) were observed in the NaCl solution. In the solutions containing BSA, a unique dual-mode biodegradation was observed. Adding BSA to a NaCl solution increased |Z| from 49 to 97 Ω·cm2 and decreased the ECN signal of the alloy, i.e., the BSA inhibited corrosion. On the other hand, the presence of BSA in Hanks' solution increased the rate of biodegradation by decreasing both Zn and |Z| while increasing ECN. Finally, using scanning Kelvin probe force microscopy (SKPFM), we observed an adsorbed nanolayer of BSA with aggregated and fibrillar morphology only in Hanks' solution, where the electrical surface potential was 52 mV lower than that of the Mg oxide layer.

Inhibition of Xanthine Oxidase by Pyrazolone Derivatives Bearing a 4-(Furan-2-yl)benzoic Acid Moiety

The pyrazolone-based 4-(furan-2-yl)benzoic acids have been synthesized and studied as xanthine oxidase inhibitors. This enzyme is one of the therapeutic targets for the treatment of hyperuricemia and related diseases. The compounds studied have found to exhibit low micromolar IC50 values relative to the enzyme in vitro, depending on substituents in position 3 of the pyrazolone ring. However, the inhibitory effects observed are reduced in the presence of bovine serum albumin or Tween-80. Among the pyrazolone derivatives synthesized, 4-(5-((3-methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)methyl)furan-2-yl)benzoic acid has been found to be the most potent inhibitor of xanthine oxidase. Kinetic results have shown that this compound is a mixed-type inhibitor with higher affinity to the free enzyme than to the enzyme-substrate complex. The results of the molecular docking and molecular dynamics show that the carboxylic group of the inhibitor can form a salt bridge with Arg880 and a hydrogen bond with Thr1010. These interactions can be key factors in the enzyme-inhibitor complex stabilization.

Statistical 3D morphology characterization of vaterite microspheres produced by engineered Escherichia coli

Hollow vaterite microspheres are important materials for biomedical applications such as drug delivery and regenerative medicine owing to their biocompatibility, high specific surface area, and ability to encapsulate a large number of bioactive molecules and compounds. We demonstrated that hollow vaterite microspheres are produced by an Escherichia coli strain engineered with a urease gene cluster from the ureolytic bacteria Sporosarcina pasteurii in the presence of bovine serum albumin. We characterized the 3D nanoscale morphology of five biogenic hollow vaterite microspheres using 3D high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) tomography. Using automated high-throughput HAADF-STEM imaging across several sample tilt orientations, we show that the microspheres evolved from a smaller more ellipsoidal shape to a larger more spherical shape while the internal hollow core increased in size and remained relatively spherical, indicating that the microspheres produced by this engineered strain likely do not contain the bacteria. The statistical 3D morphology information demonstrates the potential for using biogenic calcium carbonate mineralization to produce hollow vaterite microspheres with controlled morphologies. Statement of significanceThe nanoscale 3D structures of biomaterials determine their physical, chemical, and biological properties, however significant efforts are required to obtain a statistical understanding of the internal 3D morphology of materials without damaging the structures. In this study, we developed a non-destructive, automated technique that allows us to understand the nanoscale 3D morphology of many unique hollow vaterite microspheres beyond the spectroscopy methods that lack local information and microscopy methods that cannot interrogate the full 3D structure. The method allowed us to quantitatively correlate the external diameters and aspect ratios of vaterite microspheres with their hollow internal structures at the nanoscale. This work demonstrates the opportunity to use automated transmission electron microscopy to characterize nanoscale 3D morphologies of many biomaterials and validate the chemical and biological functionality of these materials.

Electrochemical detection of prostate specific antigen in the presence of an aptamer and composites of cobalt phthalocyanine-exfoliated graphite

This work focuses on the development of biosensor and their use for the detection of prostate specific antigen (PSA). The three cobalt phthalocyanine (CoPc) complexes, exfoliated graphite (EG), and an aptamer are used to make a probe for PSA detection. Each CoPc complex is π-π stacked onto the EG to form EG-CoPc(π-π) hybrid which was then used to modify a glassy carbon electrode (GCE). EG and CoPc were also used to modify the GCE sequential (seq) with CoPc on top to give GCE-EG-CoPc(seq). For the detection PSA, PSA specific aptamer was either adsorbed or covalently linked to the modified electrodes. Electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) were the techniques used for the detection of PSA. The electrodes were found to be selective in the presence of bovine serum albumin, glucose and cysteine and were stable when 50 DPV scans were run. The electrodes showed good % recovery when human serum was spiked with different PSA concentrations.

Microfiltration of concentrated albumin solutions and the role of processing conditions on membrane fouling

Membrane processing is a subject of growing scientific and industrial interest as a valuable technology to replace conventional energy-intensive operations, but is hindered by the progressive decrease of permeate flux caused by membrane fouling. Although physico-chemical factors affecting membrane fouling have been widely investigated, less is known concerning the effects of processing conditions. Here, we focus on microfiltration of aqueous bovine serum albumin (BSA) solutions by using a novel miniaturized modular unit allowing to study both dead-end (DE) and crossflow (CF) filtration. Pure water flux measurements and Computational Fluid Dynamics (CFD) simulations were firstly performed to characterize the flow field inside the module. In presence of BSA, at the same transmembrane pressure (TMP) of 20 mbar and average pore size of 0.45 μm, a remarkable decrease in the fouling progression with time was found for CF with a peristaltic pump as compared to pressure-driven DE filtration. Furthermore, BSA concentration in the permeate was the same as in the feed for peristaltic CF, while negligible for DE. By either increasing transmembrane pressure or lowering membrane pore size, a stronger decay of permeate flux with time was observed. Scanning electron microscopy images of the membrane showed the presence of a thick surface cake layer under peristaltic CF, which became thinner by increasing TMP or reducing membrane pore size. Overall, the better performance of peristaltic CF can be interpreted in terms of reduced BSA residence time in the membrane, membrane deformability and formation of a permeable cake layer at lower TMP and larger membrane pore size. The innovative design of our filtration module and the combination of permeate flux and concentration measurements with CFD results and microscopy observations constitute the most significant aspects of this research work, which provides a multiscale picture of membrane fouling. The insight emerging from results aims to provide qualitative guidelines towards an optimal setting of processing conditions in membrane operations, which is highly needed to improve the membrane innovation pipeline.

A Sensor for Monitoring the Antimicrobial Activity of Wound Dressings for Both Surgical Site Infections (SSIs) and Chronic Wounds.

Antimicrobial impregnated wound dressings are a critical tool for the management, prevention, and control of surgical site infections (SSIs) and infected chronic wounds. However, the sustained therapeutic antimicrobial activity of the dressing when employed for extended periods cannot be readily determined in vivo. Consequently, dressings are changed frequently to ensure that their antimicrobial activity is maintained. Whilst frequent dressing changes allow the wound to be assessed, this is time-consuming and can cause disruption to the wound bed impairing the healing process. Furthermore, this increases medical costs for the patient and hospitals. This paper introduces a novel concept to monitor the therapeutic levels of an antimicrobial component within a wound dressing ensuring the wound dressing remains "fit for purpose" and avoiding indiscriminate use of antiseptics. This could help to inform clinicians whether the antimicrobial is still being delivered at therapeutic levels and as such when to change the dressing ensuring timely positive clinical outcomes. Silver has been used historically as an antimicrobial agent and is ubiquitous in current generations of antimicrobial wound dressings. However, its activity is complex due to the poor solubility of silver ions in the presence of chloride and the effect of complexation by other components in the dressing and wound ecosystem, not least by serum proteins. In this paper, we detail an electrochemical silver sensor (5D patent protected - WO2023275553A1), constructed using a platinum (Pt) nanoband array electrode, and characterise its response to silver ions. This is determined in the presence of bovine serum albumin (BSA) and simulated wound fluid (SWF) containing chloride and rationalised using atomic analysis of the composition of the SWF. The sensor response in SWF is compared with the antimicrobial activity of silver against Pseudomonas aeruginosa in the planktonic and biofilm state, as a function of the amount of silver nitrate added. At low concentrations, silver in SWF has good solubility but reduced antimicrobial effect due to binding of silver by BSA as shown by the sensor response. At intermediate concentrations, above 10ppm, the silver was efficacious on both planktonic microorganisms and biofilm impregnated with microorganisms and readily detected with the sensor. At high concentrations, silver precipitates and both the silver in solution and the sensor response plateaus. The data demonstrates how the sensor correlates with the antimicrobial activity of the silver in vitro and how this could be used to actively monitor antimicrobials in vivo.

AIE‐Active ‘Turn‐On’ Sensors for Highly Selective Detection of Bovine Serum Albumin**

AbstractTetraphenylethylene (TPE)‐based, two molecular ‘Turn‐On’ probes i. e. 4,4′,4′′,4′′′‐(ethene‐1,1,2,2‐tetrayl)tetraphenol (tetrahydroxy‐TPE, coded as: TPE‐1) 4,4′,4′′,4′′′‐(ethene‐1,1,2,2‐tetrayl)tetraaniline and tetraamino‐TPE, coded as: TPE‐2) have been successfully reported for the selective detection of bovine serum albumin (BSA) over its other biological competitors. The BSA sensing has been investigated using UV‐Vis absorption and fluorescence emission spectroscopy, where the fluorescence of probes tetrahydroxy‐TPE and tetra‐amino‐TPE was significantly enhanced in the presence of BSA. The BSA sensing was also characterized by visual eye detection, where a significant color change of probe tetrahydroxy‐TPE and tetra‐amino‐TPE was observed with BSA. The detection limit for BSA was calculated to be 0.2 nM and 1.41 nM for using probes tetrahydroxy‐TPE and tetra‐amino‐TPE, respectively. The binding constant was observed to be1.8×103 M and 1.4×103 M for probes tetrahydroxy‐TPE and tetra‐amino‐TPE, respectively. A molecular docking study is also performed to investigate the detailed interactions between probes tetrahydroxy‐TPE and tetra‐amino‐TPE with BSA. The lowest binding energy conformation for probes tetrahydroxy‐TPE and tetra‐amino‐TPE was found at −8.1 kcal/mol and −8.2 kcal/mol, respectively.

Fluorescence “light-up” sensor based on ligand/SiO2@NH2@cyanuric chloride nanoparticle interactions in alliance with salt dehydration for berberine detection

Berberine (BBR) is an important anti-inflammatory drug for the treatment of intestinal diseases. The quantification of BBR is required in clinical medicine because long-term or excessive intake can lead to drug resistance and adverse effects. In this study, SiO2@NH2@cyanuric chloride (CNCl) nanoparticles (NPs) were successfully prepared by covalently incorporating CNCl onto the surface of SiO2 NPs. Furthermore, a novel fluorescence “light-up” sensor for assaying BBR was established based on the interaction between BBR and SiO2@NH2@CNCl NPs. Although BBR was non-emissive in aqueous media, its fluorescence was considerably augmented because of the interaction with the as-prepared SiO2@NH2@CNCl NPs, and the enhancement factor was approximately three times larger than that of pure SiO2 NPs. Compared with SiO2 NPs, SiO2@NH2@CNCl NPs can interact with BBR through electrostatic interactions and π-π stacking. These interactions restricted the intramolecular motion and charge transfer of BBR, resulting in fluorescence enhancement. The sensor was sensitive, with a linear response over a concentration range of 25–2500 nM (R2 = 0.9905) and a detection limit (3σ/k) of 4.7 nM, and it had good selectivity for BBR in the presence of bovine serum albumin, amino acids, and metal ions. When the sensor was applied to real serum samples, rapid extraction and salt dehydration occurred to improve the efficiency of pretreatment, and satisfactory standard recovery rates (95%–96%) were achieved even when only small amounts of acetonitrile was used for protein precipitation. This strategy could serve as a reference for other studies requiring the analysis of drugs in biological samples.

The Morphology Dependent Interaction between Silver Nanoparticles and Bovine Serum Albumin.

Biological applications of silver nanoparticles (AgNPs) depend on the covalently attached or adsorbed proteins. A series of biological effects of AgNPs within cells are determined by the size, shape, aspect ratio, surface charge, and modifiers. Herein, the morphology dependent interaction between AgNPs and protein was investigated. AgNPs with three different morphologies, such as silver nanospheres, silver nanorods, and silver nanotriangles, were employed to investigate the morphological effect on the interaction with a model protein: bovine serum albumin (BSA). The adsorptive interactions between BSA and the AgNPs were probed by UV-Vis spectroscopy, fluorescence spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), and circular dichroism (CD) techniques. The results revealed that the particle size, shape, and dispersion of the three types of AgNPs markedly influence the interaction with BSA. Silver nanospheres and nanorods were capsulated by protein coronas, which led to slightly enlarged outer size. The silver nanotriangles evolved gradually into nanodisks in the presence of BSA. Fluorescence spectroscopy confirmed the static quenching the fluorescence emission of BSA by the three AgNPs. The FTIR and CD results suggested that the AgNPs with different morphologies had different effects on the secondary structure of BSA. The silver nanospheres and silver nanorods induced more pronounced structural changes than silver nanotriangles. These results suggest that the formation of a protein corona and the aggregation behaviors of AgNPs are markedly determined by their inherent morphologies.

Environment-sensitive indolenine-based hemisquaraine dyes: Synthesis, molecular structure, and spectral properties

Environment-sensitive fluorescent dyes are widely used in biomedical research, clinical diagnostics, molecular and cellular biology, analytical and bioanalytical chemistry. Many sensing dyes in the series of cyanines, styryls, BODIPY, squaraines, fluoresceins, and rhodamines among others have been developed and employed for these applications. Meanwhile, push-pull hemisquaraine dyes have been only moderately explored as the environment sensors. Herein, we developed a series of hemisquaraine dyes containing methylamino (MeH), dimethylamino (MeMe), phenylamino (PhH), phenylmethylamino (PhMe), and diphenylamino (PhPh) groups. These substituents were found to strongly affect sensitivity of the dyes towards H-bond formation, polarity, pH, viscosity, and the presence of bovine serum albumin (BSA), which aids the development of sensors for particular applications.

Investigation of the noncovalent interactions of the Cu (II) amine complex with flexible aromatic moiety to the interaction with bovine serum albumin

In crystallographic studies, non-covalent interactions are identified based on which atom is involved. A more accurate and quantitative idea can be obtained from the Hirshfeld surface (HS) analysis of the crystal structure of the molecule. The crystal structure of the synthesized Cu(II) complex (azidobis(N-benzylethylenediamine)copper(II) azide) with N-benzylethylenediamine was investigated to identify all the non-covalent interactions present in the crystal. Apparently, the hydrogen bond was the leading force in constructing the crystal from the crystallographic study, and this idea was overruled by HS analysis. The HS study indicates van der Walls interactions majorly contribute to crystal formation. Again, the high energy gap between HOMO and LUMO showed the inertness of the molecule toward chemical reactions. The conformational analysis of the molecule showed that the Cu(II) complex has a flexible phenyl ring and covalent azide, which makes the complex adjustable according to the environment. All these features of the complex make it a good candidate for interaction with proteins. In the presence of bovine serum albumin (BSA), the complex preferred to go into the hydrophobic site of the protein from water due to its van der Walls interactions preference. The interaction of the complex with BSA was investigated with multi-spectroscopic methods like UV–vis, fluorescence, circular dichroism, and time-resolved fluorescence lifetime. The experimental results also support the theoretical prediction that the binding of the complex with BSA is through hydrophobic interactions. Molecular docking results also indicate the hydrophobic interactions play the BSA-complex conjugation.

Evaluation of Antibacterial Activity of Selenium Nanoparticles against Food-Borne Pathogens.

Selenium is an essential micronutrient for all mammals and plays an important role in maintaining human physiological functions. Selenium nanoparticles (SeNPs) have been shown to demonstrate antioxidant and antimicrobial activity. The objective of this study was to explore whether SeNPs have the potential to be used as food preservatives with which to reduce food spoilage. SeNPs were synthesized through ascorbic acid reduction of sodium selenite (Na2SeO3) in the presence of bovine serum albumin (BSA) as a capping and stabilizing agent. The chemically synthesized SeNPs had a spherical conformation with an average diameter of 22.8 ± 4.7 nm. FTIR analysis confirmed that the nanoparticles were covered with BSA. We further tested the antibacterial activity of these SeNPs against ten common food-borne bacteria. A colony-forming unit assay showed that SeNPs exhibited inhibition on the growth of Listeria Monocytogens (ATCC15313) and Staphylococcus epidermidis (ATCC 700583) starting at 0.5 µg/mL, but higher concentrations were required to slow down the growth of Staphylococcus aureus (ATCC12600), Vibrio alginolyticus (ATCC 33787), and Salmonella enterica (ATCC19585). No inhibition was observed on the growth of the other five test bacteria in our study. Our data suggested that the chemically synthesized SeNPs were able to inhibit the growth of some food-borne bacteria. The size and shape of SeNPs, method of synthesis, and combination of SeNPs with other food preservatives should be considered when SeNPs are to be used for the prevention of bacteria-mediated food spoilage.

Role of Bovine Serum Albumin Addition in Micellization and Gel Formation of Poloxamer 407.

The combination of the thermoresponsive polymer and protein has demonstrated great promise in its applications in drug delivery and tissue engineering fields. This study described the impact of bovine serum albumin (BSA) on the micellization and sol-gel transition behaviors of poloxamer 407 (PX). The micellization of aqueous PX solutions with and without BSA was examined using isothermal titration calorimetry. In the calorimetric titration curves, the pre-micellar region, the transition concentration region, and the post-micellar region were observed. The presence of BSA had no noticeable impact on critical micellization concentration, but the inclusion of BSA caused the pre-micellar region to expand. In addition to studying the self-organization of PX at a particular temperature, the temperature-induced micellization and gelation of PX were also explored using differential scanning calorimetry and rheology. The incorporation of BSA had no discernible effect on critical micellization temperature (CMT), but it did affect gelation temperature (Tgel) and gel integrity of PX-based systems. The response surface approach illustrated the linear relation between the compositions and the CMT. The major factor affecting the CMT of the mixtures was the concentration of PX. The alteration of the Tgel and the gel integrity were discovered to be a consequence of the intricate interaction between PX and BSA. BSA mitigated the inter-micellar entanglements. Hence, the addition of BSA demonstrated a modulating influence on Tgel and a softening effect on gel integrity. Understanding the influence of serum albumin on the self-assembly and gelation of PX will enable the creation of thermoresponsive drug delivery and tissue engineering systems with controlled gelation temperatures and gel strength.

Study of protein encapsulated manganite nanoparticles for magnetic Hyperthermia

Used in the past as an efficient drug-delivery carrier, the natural protein Bovine Serum Albumin (BSA) has been tried in the present study to coat Lanthanum Strontium Manganese Oxide (LSMO) nanoparticles (NPs) called manganite, for magnetic Hyperthermia applications. LSMO NPs generate heat when subjected to a radiofrequency magnetic field and as a novel attempt; they were functionalized with BSA by its “denaturation” at 80°C. This was done to probe the effect of protein bonding with nanoparticles by “unfold” of its molecular structure and to enhance the biocompatibility of LSMO. Presence of BSA on NPs was assessed through electron microscopy (HRTEM), Fourier transform (IR) spectroscopy and thermogravimetric analysis (TGA); that showed successful outcomes. The magnetization was analyzed by super quantum interface device (SQUID). For Hyperthermia studies, BSA coated NPs were dispersed in phosphate buffer saline and attained an appreciable specific absorption rate of 126.9 W/g showing their potential for future applications.

Thermoregulation of Hydrogel Spatiotemporal Mechanics by Exploiting the Folding-Unfolding Characteristics of Globular Proteins.

The incorporation of proteins into hydrogel networks has the potential to enhance bioactivity and biocompatibility. In this work, we report on the fabrication of a polymer-protein hydrogel consisting of polymethacrylamide (PMAAm) and bovine serum albumin (BSA). The hydrogel was prepared by in situ polymerization of methacrylamide in the presence of BSA at elevated temperatures. Due to its specific interactions between corresponding functional groups, BSA acts as a cross-linker of polymer chains. Hydrogel with optimized composition and preparation conditions (BSA/methacrylamide ratio and synthesis temperature) demonstrated excellent mechanical properties. Due to the presence of side amide groups in PMAAm, the energy barrier required for heat-induced transformation of globular BSA structures into unfolded linear structures decreased, causing a significant shift in the transition temperature. This transition led to a steep and substantial strengthening of the two-component hydrogel. After compressive and shear deformation, the hydrogel restored damaged structure and demonstrated superior fatigue resistance. Compared to BSA that is globular, it was found that BSA in its unfolded state has a much greater impact on the mechanical properties of the hydrogel.

Interaction of Hyaluronan Acid with Some Proteins in Aqueous Solution as Studied by NMR

According to actual literature data, hyaluronic acid (HA) that is presented in the extracellular matrix can interact with proteins and thereby affect several important functions of the cell membrane. The purpose of this work was to reveal the features of the interaction of HA with proteins using the PFG NMR method by sampling two systems: aqueous solutions of HA with bovine serum albumin (BSA) and aqueous solutions of HA with hen egg-white lysozyme (HEWL). It was found that the presence of BSA in the HA aqueous solution initiates a certain additional mechanism; as a result, the population of HA molecules in the gel structure increases to almost 100%. At the same time, for an aqueous solution of HA/HEWL, even in the range of low (0.01-0.2%) HEWL contents, strong signs of degradation (depolymerization) of some HA macromolecules were observed such that they lost the ability to form a gel. Moreover, lysozyme molecules form a strong complex with degraded HA molecules and lose their enzymatic function. Thus, the presence of HA molecules in the intercellular matrix, as well as in the state associated with the surface of the cell membrane, can, in addition to the known ones, perform one more important function: the function of protecting the cell membrane from the destructive action of lysozymes. The obtained results are important for understanding the mechanism and features of the interaction of extracellular matrix glycosaminoglycan with cell membrane proteins.

A good and bad aggregation: Effect of imidazolium- and cholinium-based ionic liquids on the thermal stability of bovine serum albumin

The present work describes the effect of imidazolium- and cholinium-based ionic liquids (ILs) on the thermal stability, binding and aggregation of bovine serum albumin (BSA). The studied ILs include choline chloride [Ch][Cl], choline dihydrogenphosphate [Ch][DHP], choline acetate [Ch][OAc], 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], 1-octyl-3-methylimidazolium tetrafluoroborate [OMIM][BF4] 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][TfO], 1-butyl-3-methylimidazolium acetate [BMIM][OAc], and 1-butyl-3-methylimidazolium methanesulfonate [BMIM][CH3SO3]. The state of BSA in presence of ILs was assessed by circular dichroism (CD), temperature dependent circular dichroism, fluorescence spectroscopy, and dynamic light scattering (DLS). The thermal stability of BSA in presence of ILs increased (above 85 °C) in all studied ILs except [OMIM][BF4]. Differences of binding ILs with BSA depending on alkyl chain length were estimated, the probable binding modes were identified using molecular docking. The influence of ILs on the aggregation of BSA at different temperatures was established. It was found that the ILs with short alkyl chain length (up to butyl) promote aggregation of the native form of BSA increasing its thermal stability.

IMPROVEMENT IN OSTEOCONDUCTIVITY OF MINISCREW IMPLANTS BY THE BIOMIMETIC CALCIUM PHOSPHATE COATINGS IN THE PRESENCE AND ABSENCE OF BOVINE SERUM ALBUMIN

Miniscrew implants (MSIs) are widely used to provide absolute anchorage for the orthodontic treatment. However, the application of MSIs is limited by the relatively high failure rate (22.86%). In this study, we wished to investigate the effects of amorphous and crystalline biomimetic calcium phosphate coating on the surfaces of MSIs with or without the incorporated BSA for the osteointegration process with an aim to facilitate the early loading of MSIs.Amorphous and crystalline coatings were prepared on titanium mini-pin implants. Characterizations of coatings were examined by Scanning electron microscopy (SEM), Confocal laser-scanning dual-channel-fluorescence microscopy (CLSM) and Fourier-transform infrared spectroscopy (FTIR). The loading and release kinetics of bovine serum albumin (BSA) were evaluated by Enzyme linked immunosorbent assay (ELISA). Activity of alkaline phosphate (ALP) was measured by using the primary osteoblasts. In vivo, a model of metaphyseal tibial implantation in rats was used (n=6 rats per group). We had 6 different groups: no coating no BSA, no coating but with surface adsorption of BSA and incorporation of BSA in the biomimetic coating in the amorphous and crystalline coatings. Time points were 3 days, 1, 2 and 4 weeks. Histological and histomorphometric analysis were performed and the bone to implant contact (BIC) of each group was compared.In vitro, the incorporation of BSA changed the crystalline coating from sharp plates into curly plates, and the crystalline coating showed slow-release profile. The incorporation of BSA in crystalline coating significantly decreased the activity of ALP in vitro. In vivo study, the earliest significant increase of BIC appeared in crystalline coating group at one week.The crystalline coating can serve as a carrier and slow release system for the bioactive agent and accelerate osteoconductivity at early stage in vivo. The presence of BSA is not favorable for the early establishment of osteointegration.

Effects of proteins on magnesium degradation - static vs. dynamic conditions

The interaction between organic molecules and biomaterial surfaces determines the fate of biomaterials during their service life, which is also the research hotspots in the field of biomaterials. To understand the mechanism of protein interaction with magnesium (Mg) degradation, alloying elements, immersion time, protein concentration and surface conditions have been previously considered for the effect of proteins on Mg degradation. However, fluid flow, as one of the critical factors, drew little attention in this case. In the present study, the effect of bovine serum albumin (BSA) and fetal bovine serum (FBS) on Mg degradation was compared under static and dynamic conditions. The results revealed that both BSA and FBS slightly decreased the degradation rate of Mg in Hanks’ balanced salt solution (HBSS) under static immersion due to the protein adsorption and the formation of a Ca/P-rich top layer on Mg surface, whereas under dynamic flow condition the degradation of Mg was significantly accelerated in the presence of BSA or FBS. The reasons seemed to stem from the weakened protein adsorption on Mg surface in this case and the dynamically enhanced interaction between proteins and ions/products in solutions, which largely weaken the combination of the top Ca/P-rich layer with the inner corrosion product layer. These results highlight the importance of testing conditions for Mg characterization in vitro and the synergistic effect between different parameters on Mg degradation.