Biospecific Properties Research Articles

Modification of eggshell membrane to impart biospecific properties

AbstractEggshell membrane (ESM) represents an inexpensive, environmentally friendly and nontoxic byproduct. Besides the unique mechanical properties of the material, the ESM surface is rich in functional groups susceptible to further modifications. In the current study two modification pathways were applied to enrich the ESM surface with glucopyranosyl units. One was based on the reaction of activated surface carboxylic groups with glucosamine and the other exploited the reactivity of the surface amino groups for grafting poly(ethylene glycol) (PEG) chains bearing end glucopyranosyl and benzaldehyde moieties. The functionalization of the PEG chains with molar masses 400 and 1500 g mol−1 was evidenced from 1H NMR and 13C NMR spectral data. The modified ESMs were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The Brunauer–Emmett–Teller specific surface area and the total pore volume of ESM decreased upon modification. Decoration of ESM with glucopyranosyl units imparted protein recognition properties that were tested via binding studies with concanavalin A as model lectin. Further, grafting of glucose units via PEG linkers reduced bacterial adhesion onto the membrane surface. © 2021 Society of Industrial Chemistry.

Applicability of modified carbon sorbent for removing potentially toxic biologically active molecules of aromatic structure from blood plasma.

The modification of the mesoporous carbon sorbent with 3-phenylpropanoic acid was carried out in order to create preparations of complex, prolonged action, exhibiting detoxifying, antibacterial, and antifungal properties due to the applied modifier, which is capable of migrating into the solution and exhibiting its own biospecific properties. A technique was developed for fixing 3-phenylpropionic acid (PhPA) on a carbon support by its adsorption from solution. Three types of sorbents with various content of the modifier (PhPA) and the sorbent without modifier were studied. The sorption activity of new sorbents was studied using liquid-liquid extraction and gas chromatography-mass spectrometry methods on model experiments with plasma and aqueous additives of hydroxylated phenyl-containing acids (PhCAs) in various concentrations. The specific surface area was significantly changed for sorbent, modified with 1 × 10-3 mol/L of PhPA solution, and was 25% less than the area of unmodified sorbent. Potentially toxic biologically active hydroxylated PhCAs were used to create model solutions. The degrees of sorption of these compounds were close to 100%, except phenyllactic acid (over 80%). The sorbent without modifier and two sorbents with the lowest content of the modifier are considered to be more effective for the purification of the plasma from the hydroxylated PhCAs than the sorbent with the highest concentration of the modifier. Simultaneous adsorption of toxic metabolites from the bloodstream and desorption of beneficial ones can be used for a more subtle correction of the patient's condition.

A Physicochemical Study of the Process of Modification of Carbon Sorbents with Lactic Acid

With the aim of creating new adsorbing materials with biospecific properties for applications in medicine (obstetrics and gynecology), a technique for the chemical modification of a molded carbon sorbent with lactic acid by polycondensation of the latter on the surface of the former without catalysts is proposed. The completeness of the process of polycondensation of lactic acid on a molded carbon sorbent was controlled by physicochemical methods (low-temperature nitrogen absorption and thermal analysis). The amount of the deposited modifier (lactic acid oligomer) is a determining factor of the completeness of the modification process, which is determined from the results of thermogravimetric analysis of samples. The optimal conditions of the impregnation and thermal processing of a molded carbon sorbent, under which the amount of the deposited modifier reaches the maximum value and equals 7.2–10.5 wt %, have been chosen on the basis of the results of studies. The elemental composition and the content of surface functional groups of the two most promising samples of modified molded carbon sorbents are analyzed. These modified samples are of interest for further analyses and a study of their adsorption properties.

A study of desorption (migration) of oligomers/copolymer of hydroxy acids from the surface of modified sorbents in aqueous solutions

The desorption of oligomers/copolymer of glycolic and lactic acids from the surface of the synthesized modified sorbents in a 0.9% NaCl saline solution was studied by means of 1H NMR spectroscopy, pH-metering and low-temperature nitrogen adsorption. It was found that contact of the modified sorbents with a saline solution leads to a gradual desorption of the modifiers with biospecific properties as mono-, di- and trimers from the sorbent surface via hydrolysis. The desorption of deposited modifiers was shown to increase specific surface area of the material and decrease pH of the medium. A low (<4) pH of the biological medium, which is obtained upon contacting with the modified sorbent, will promote the death of pathogens and infectious agents. The synthesized carbon materials can be recommended for use in sorption therapy

Synthesis and physicochemical properties of a biospecific carbon sorbent modified with lactic-acid oligomers

A method of lactic-acid (LA) polycondensation on a carbon sorbent, including sorbent impregnation and multistep thermal treatment with no catalysts or toxic solvents, is developed. This modification technique makes it possible to obtain materials with adjustable properties (molecular weight of the synthesized oligomer, amount of applied modifier, degree of screening of carbon-sorbent pores, etc.). The resulting sorbent samples were investigated using various physicochemical methods: 13С and 1Н NMR spectroscopy, low-temperature nitrogen adsorption, differential thermal analysis, etc. It is established that the modifier concentration has an impact on the physicochemical characteristics of the studied carbon-sorbent samples. Of greatest interest is the carbon-sorbent sample impregnated with a 50% lactic-acid solution with subsequent thermal treatment. Its composition includes a high content of the modifier (biologically active substance with biospecific properties) and exhibits durable action.

Synthesis and Research of Modified Carbon Sorbents with Hydroxy Acids

The results on the synthesis and study of modified materials for medical application based on nanodispersed carbon are given. Modification of the carbon sorbent was performed using the biologically active substances with biospecific properties – hydroxy acids (glycolic and lactic). The main results obtained by investigation of the modified carbon sorbents by physicochemical and biomedical methods are presented.

Perspective Directions of Synthesis of Materials with Biospecific Actions Based on Nanodispersed Carbon

The results of long-term researches and development of modified materials for medical and veterinary application based on nanodispersed carbon are given. Complex of methods of chemical functionalization of carbon sorbents surface with biospecific properties is described. The main results of modified carbon sorbent researches by physiochemical and biomedical methods are represented.

Aptamer‐Directed Synthesis of Multifunctional Lanthanide‐Doped Porous Nanoprobes for Targeted Imaging and Drug Delivery

Multifunctional lanthanide-doped porous nanoparticles are prepared via a facile one-step solvothermal route by employing aptamers as the biotemplate. The nanoparticles feature excellent aqueous dispersibility and biospecific properties and could work as effective nanoprobes for targeted imaging and drug delivery. With aptamer being in principle available for any kind of target, this synthetic strategy may open the door to a new generation of nanoprobes for bioapplications such as time-resolved biodetection, multimode bioimaging/biolabeling, and targeted cancer therapy.

Aqueous synthesized near-infrared-emitting quantum dots for RGD-based in vivo active tumour targeting

Over the past two decades, fluorescent quantum dots (QDs) have been highly attractive for a myriad of bioapplications due to their unique optical properties. For bioimaging applications, QD-based in vivo specific tumour targeting is vitally important in the biological and biomedical fields. Aqueous synthesized QDs (aqQDs) exhibit excellent aqueous dispersibility without requiring any post-treatment and have small hydrodynamic diameters (generally <5 nm), which are highly useful for bioimaging applications. We herein present the first example of in vivo active tumour targeting using water-dispersed near-infrared-emitting aqQDs modified with Arg-Gly-Asp (RGD) peptides. In vitro and in vivo studies (e.g., tumour cell labelling, histological analysis, and active tumour targeting) demonstrate that the prepared RGD-decorated aqQDs exhibit highly bio-specific properties, enabling sensitive and specific targeting of tumour sites in both cells and living animals. Our results suggest that the new class of RGD-decorated aqQDs are highly promising as fluorescent bioprobes for a wide range of biological applications.

In vitro modeling of cell-scaffold interaction

The simple approach for modeling of surface ligand - cell receptor interaction is proposed to control the effectiveness of peptide acceptor selected to be immobilized on a scaffold surface in order to promote specific cell adhesion and their subsequent proliferation and bone tissue formation. For experimental realization of such approach the affinity chromatography with use of macroporous monolithic sorbent is suggested. The biospecific GRGDSP-peptide performed the role of scaffold surface ligand which is responsible for cell adhesion, while the "cells" were simulated by polymer (polystyrene) micro particles with EDYPVDIYYLM-DLSYSMKDD-peptide immobilized on their surface. The latter peptide is the integrin molecule active site which is responsible for RGD-sequence binding. Thus the ultra-short monolithic chromatography columns (CIM-disks) represent the simplified model of a scaffold possessing biospecific properties. The qualitative evaluation of complement interaction parameters was performed via frontal analysis method followed by adsorption isotherm plotting and subsequent linearization and mathematical treatment. The data obtained reliably indicate the highly specific character of biological pair binding. This was in a good accordance with results obtained in the cell culture experiments.

Biospecific properties of lysine-containing polyelectrolyte coatings for blood contacting devices

Biospecific properties of thromboresistant bilayer and multilayer coatings based on polyelectrolyte complexes of modified copolymer of N-vinylpyrrolidone and maleic acid (VPMA) with chitosan, amphiphilic chitosan or albumin were investigated. VPMA contained an affinity ligand towards plasminogen, α-amino coupled lysine residues. Polyethylene and polystyrene surfaces were investigated before and after their covering by protective polyelectrolyte coatings. The specific adsorption of plasminogen (precursor of the fibrinolytic enzyme plasmin) from its solutions and from human plasma was investigated using these model systems. It was found that all coatings with the outer contact layer of the lysine-containing affinity polymer exhibited affinity towards plasminogen. However, multilayer polyelectrolyte coatings were more efficient than the bilayer coatings with a single layer application and the affinity polymer coatings without interlayer. The decrease in the degree of thrombogenicity of the materials modified by polyelectrolyte coatings has been demonstrated in vitro and ex vivo. Employment of the proposed modification of surfaces will improve hemocompatibility of medical devices.

Application of adsorption kinetics for estimation of dissociation constants

Substances such as drugs, as well special ligands with expressive biospecific properties, all with different affinities, interact with proteins which can be characterized by dissociation constants. The method for estimation of the dissociation constant on the basis of adsorption kinetic was verified for two typica cases: adsorption of lactate dehydrogenase onto bed cellulose derivatized by reactive dyes C.I.2. or C.I.19, and adsorption of different drugs (neuroleptics and local anesthetics) onto calmodulin immobilized on agarose gel. The real equilibrium values obtained by using the complete time-concentration model of adsorption were fitted according to the respective adsorption isotherms by non-linear regression.

Fractionation of membrane vesicles: I. A separation method for different populations of membrane vesicles of thymocytes by affinity chromatography on Con A-Sepharose

Affinity chromatography, a separation technique which makes use of biospecific properties, is well established for the separation of molecules in solution. We applied this method to the subfractionation of biomembranes. Using a microsomal fraction mainly consisting of plasma membrane from rabbit or calf thymocytes, 20–40% of the protein adhered specifically to concanavalin A-Sepharose, whereas the majority of the membrane vesicles were recovered from the effluent. The adherence involved the binding of Con A to membranes, as addition of the hapten sugar α-methyl-mannoside completely prevented separation. The fractions which bound to Con A-Sepharose could be eluted by combining mechanical forces with the addition of α-methyl-mannoside. All fractions exhibited the same vesicular appearance and were identical with respect to the phospholipid cholesterol ratio. The method proved to be highly reproducible and it offers a possible way for the subfractionation of membranes according to their biospecific structure.