Methods and prospects of development of the affinitive sorbents for plasminogen isolation from human blood plasma

The review paper was dedicated to development of the promising photochemical synthesis of affine sorbents for plasminogen isolation from the human blood plasma. Some most interesting, from the viewpoint of practice, types of sorbents and carriers based on high-molecular compounds of natural (organic) or synthetic origin have been considered. The advantages of the use of photochemical synthesis of biospheric sorbent as compared with thermochemical method have been shown. The most promising methods of creation of affine sorbents on the basis of oligomer-polymeric photoinitiators and oligomerpolymeric photosensibilizing (donor-acceptor) systems are presented.     

DNA aptamer-based sorbents for binding human IgE

DNA aptamer-based sorbents were synthesized for binding human IgE. Sorbents effectively removed IgE from human blood plasma. The experimental values of IgE desorption constants were within the range of 1.1 × 10^?10 to 1.7 × 10^?10 M depending on the orientation of the aptamer on an insoluble matrix. The sorbents were stable during multiple use. Conditions for sorbent regeneration were selected. These chromatographic materials can be used for medical and biotechnological applications.     

Wheat Germ Lectin Sorption by Chitosan Polyelectrolyte Complexes

The possible application of polyelectrolyte complexes (PEC) of chitosan and copolymers of maleic acid with N-vinylpyrrolidone, styrene, and ethylene and/or cross-linked chitin sorbents (CLCS) synthesized on the basis of PEC for sorption of wheat germ lectin (WGL) was studied. The synthesis of spherically granulated sorbents was shown. Compared to unmodified chitosan, there was a significant increase in sorption capacity of WGL by the sorbents: PEC, 2.5-fold, and CLCS, from 3.5-fold to 7-fold.     

Affinity chromatography of proteolytic enzymes on silica-based biospecific sorbents

New biospecific sorbents for affinity chromatography of proteolytic enzymes were prepared by the attachment of the cyclopeptide antibiotics bacitracin, bacilliquin or gramicidin S to aminosilochrom via a reaction with p-benzoquinone. The content of the cyclopeptide ligands within the sorbents varied from 2 to 46 mumol/g. The sorbents prepared by this reaction were successfully applied in the purification of the carboxylic proteinases produced by fungi, Russula decolorans (a basidiomycete) and Trichoderma lignorum, as well as crude pepsin. Serine proteinases from Thermoactinomyces vulgaris, Trichoderma koningii, Trichoderma lignorum and bacilli (subtilisins) were also submitted to chromatography on these materials. The yields of purified enzymes approached quantitative levels, sometimes being higher as a result of elimination of inhibitors. An important advantage of these sorbents is their stability against the enzymes degrading the carbohydrate matrixes of affinity sorbents synthesized on the basis of agarose, dextran or cellulose derivatives.     

A new chromatographic method for the preparative isolation of phosphoinositides and other anionic phospholipids

A new chromatographic procedure for preparative isolation of mono-, di- and triphosphoinositides and other anionic phospholipids with the use of adsorbents containing primary amino groups is described. Sorbents with immobilized neomycin, L-lysine and aminoalkyl groups were tested. Conditions for isolation of chromatographically pure phospholipids of separate classes on the above sorbents were developed. Isolation of polyphosphoinositides on the amino sorbents represents a new type of chromatography involving bioaffinity and ion-exchange interaction.     

Oil removal from used sorbents using a biosurfactant

Oil spills impose serious damage on the environment. Mechanical recovery by the help of oil sorbents is one of the most important countermeasures in oil spill response. Most sorbents, however, end up in landfills or in incineration after a single use. These options either produce another source of pollution or increase the oil recovery cost. In this study a biosurfactant was used to clean used oil sorbents. This use of biosurfactants is new. Washing parameters tested included sorbent type, washing time, surfactant dosage and temperature. It was found that with biosurfactant washing more than 95% removal of the oil from sorbents was achieved, depending on the washing conditions. Biosurfactants were found to have considerable potential for recycling the used sorbents.     

Harvesting of Microalgae Biomass with Polyethylenimine-Based Sorbents

The purpose of this work was to investigate the sorbents on the basis of polyethylenimine (PEI) intended for collecting biomass of microalgae (MA). For this purpose, a series of porous and insoluble polymeric materials were synthesized by cross-linking of PEI with epichlorohydrine. The analysis of kinetics and efficiency of immobilization assessed for the model culture Chlorella vulgaris, revealed that already within 3 h of incubation, 39–75% of MA cells attached to the surface of tested sorbents. It was shown that on the initial stage of immobilization the sorption activity of polymeric materials depended on the “PEI:crosslinker” ratio. One of the tested sorbents was additionally quartenized by alkylation with dimethyl sulphate resulting in sharp increase of its sorption activity. The estimation of the MA desorption from polymeric surface showed that most Ch. vulgaris cells were practically irreversibly immobilized on all tested sorbents based on the PEI cross-linked with epichlorohydrine.     

Non-conventional low-cost adsorbents for dye removal: a review

Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those that are not easily biodegradable. Dyes represent one of the problematic groups. Currently, a combination of biological treatment and adsorption on activated carbon is becoming more common for removal of dyes from wastewater. Although commercial activated carbon is a preferred sorbent for color removal, its widespread use is restricted due to high cost. As such, alternative non-conventional sorbents have been investigated. It is well-known that natural materials, waste materials from industry and agriculture and biosorbents can be obtained and employed as inexpensive sorbents. In this review, an extensive list of sorbent literature has been compiled. The review (i) presents a critical analysis of these materials; (ii) describes their characteristics, advantages and limitations; and (iii) discusses various mechanisms involved. It is evident from a literature survey of about 210 recent papers that low-cost sorbents have demonstrated outstanding removal capabilities for certain dyes. In particular, chitosan might be a promising adsorbent for environmental and purification purposes.     

Sorption of wheat seed lectin by polyelectrolyte complexes of chitosan

The possible application of polyelectrolyte complexes (PEC) of chitosan and copolymers of maleic acid with N-vinylpyrrolidone, styrene, and ethylene and/or chitin cross-linked sorbents (CCLS) synthesized on the basis of PEC for sorption of wheat germ agglutinin (WGA) was studied. The synthesis of spherically granulated sorbents was shown. Compared to unmodified chitosan, there was a significant increase in sorption of WGA by the PEC: PEC, 2.5-fold, and CCLS, from 3.5-fold to 7-fold.     

Preparation of affinity sorbents with immobilized synthetic ligands for therapeutic apheresis

The practical aspects of preparation and stability of medical sorbents are considered. A simple and convenient technique has been developed for synthesis of highly effective biospecific autoclavable sorbents based on the polysassharide matrix; synthetic ligands (amino acid, oligopeptide, or oligosaccharide) containing primary amino group were immobilized to the matrix via a spacer. The developed approach may be used for preparation of various affinity sorbents suitable for application in medicine and biotechnology.     

Composite fluorine polymer-containing sorbents for isolation and purification of biopolymers

Composite fluoropolymer-containing sorbents based on porous silicas were synthesized for the isolation and purification of biopolymers under nondenaturing conditions. Examples of the application of these sorbents in the separation of various mixtures of peptides and proteins and purification of nucleic acids from various sources (plasmid DNA and DNA from nucleated human blood cells) using the cartridge, column, and batch (sorption in a stirred volume) methods are presented. It was shown that the sorbents can be used in laboratory practice because they are selective to nucleic acids (DNA and RNA) and proteins. These materials combine the mechanical properties of the inorganic matrix with the specific sorption properties of the polymer phase and exhibit enhanced stability to alkaline hydrolysis. Alternative methods of preparing sorbents containing polytetrafluoroethylene, polytrifluorostyrene, and polyfluorobutadiene are described. By the example of polyfluorobutadiene-containing sorbents, a completely new method for obtaining fluorinated polymer phases was developed: the polymer phase was preliminarily formed on the surface of porous disperse carriers and was fluorinated with xenon difluoride.     

Isolation of nisin from native solution and its purification on cationites]

It was found possible to use organic sorbents and in particular carboxylic cationites for isolation of nisin from the fermentation broth filtrate and its purification. Nisin is known as a polypeptide antibiotic applied as a preservative. The sorbents were shown to have high exchange capacities by the isolated substance and mechanical strength and resistance. They also proved to be highly stable.     

Immobilization of cyanobacteria and microalgae on polyethylenimine-based sorbents

Immobilization of phototrophic microogranisms: microalgae (MA) and cyanobacteria (CB) on polyethylenimine (PEI)-based sorbents was studied. For this purpose, 3 insoluble porous polymeric materials were synthesized by cross-linking of PEI with epichlorohydrine and immobilization of PEI on the surface of styrene–divinylbenzene copolymer. The sorbent on the basis of cross-linked PEI was also alkylated with hexadecyl bromide to achieve hydrophobicity of its surface. The analysis of kinetics and efficiency of immobilization assessed for the model MA and CB cultures revealed the significant difference in the sorption activity of different types of sorbents depending on their synthesis procedure, chemical composition and hydrophilic-hydrophobic properties of polymeric surface. The hydrophobic sorbent obtained by immobilization of PEI on the surface of styrene–divinylbenzene copolymer characterized by very low sorption activity towards CB and MA cells. The highest immobilization efficiency of phototrophic cells was achieved for the hydrophilic sorbent on the basis of PEI cross-linked with epichlorohydrine, which provided the attachment of 50–70% of cells during 3 h of incubation. The hydrophobic sorbent based on alkylated cross-linked PEI effectively immobilized CB cells, while the colonization of the polymer surface by MA cells was very scarce. The noticed effect is explained by difference in prokaryotic (CB) and eukaryotic (MA) types of surface structures organization. Assessment of photosynthetic activity of immobilized MA cells by pulse-modulated fluorometry showed that hydrophobic sorbents had no toxic effect on the cells, while toxicity of hydrophilic cross-linked PEI-based sorbent was observed only after long-term cultivation ofphototrophic cells with this sorbent.     

Molecularly imprinted hydrophilic polymer sorbents for selective sorption of erythromycin

New hydrophilic polymer sorbents comprising reactionary sites which are complementary to a molecule of antibiotic erythromycin were synthesized by the method of molecular imprinting. A series of similar sorbents without reactionary sites was used for comparison of sorption characteristics. Sorption of erythromycin on both types of polymer sorbents synthesized was studied in a wide range of pH and ionic strength. Selectivity of erythromycin sorption on molecularly imprinted cross-linked polymers was shown to depend on the specific interaction of target molecule with polymer matrix. This type of sorbent is perspective for the development of antibiotic purification directly from a culture medium Saccharopolyspora erythreus.     

A number of sorbents useful for the sorption of cephalosporin C

The physicochemical and sorption properties of a number of sorbents made in the USSR and abroad were studied with respect to the recovery of cephalosporin C from a model solution. It was shown that the sorption capacity of a sorbent depended on its specific surface. The macroporous styrene divinylbenzene sorbents with a specific surface of more than 500 m2/g had the best sorption properties.     

Use of monolithic sorbents modified by directly synthesized peptides for affinity separation of recombinant tissue plasminogen activator (t-PA)

Present report demonstrates the examples of practical application of sorbents obtained via direct solid phase peptide synthesis (SPPS) on GMA-EDMA monoliths (CIM Disks, BIA Separations, d.o.o., Ljubljana, Slovenia). Several peptidyl complementary to recombinant tissue plasminogen activator (t-PA) ligands have been synthesized using Fmoc-chemistry. This approach affords to get directly sorbents for affinity chromatography avoiding a cleavage of synthesized peptides from a carrier following by their isolation, analysis and purification. The affinity binding parameters were found from experimental frontal analysis data. The results have been compared with those established for CIM affinity sorbents obtained by immobilization of the same but preliminarily synthesized on convenient resin, cleaved and purified ligands on the disks using one step reaction with epoxy groups of monolithic material. It has been shown that the affinity constants of these two kinds of sorbent did not vary significantly. Directly obtained affinity sorbents have been used for fast and efficient on-line analysis as well as semi-preparative isolation of recombinant t-PA from crude cellular supernatant.     

Preparation and use of magnetic sorbents for studying microorganism antigens

In this work simple techniques for obtaining polyacrylamide sorbents with magnetic properties are described. These techniques have permitted obtaining block and microgranulated sorbents with the immobilization of antibodies from plague antiserum in the cellular gel structure for the specific sorption of killed and live Yersinia pestis cells and their first fraction; pig brain gangliosides have also been incorporated into the gel structure with a view to the sorption of cholera toxin from the filtrate of Vibrio cholerae culture. The magnetic properties of sorbents, obtained by the copolymerization of powdered magnetic ferric oxides in gel, have made it possible to increase the effectiveness of specific sorption due to mixing and rapid separation in different magnetic fields, as well as to facilitate and accelerate manipulations with the sorbent at all stages. The capacity of different types of sorbents and the time of sorption have been determined.     

A new approach to the depletion of albumin and immunoglobulin G from human serum

The use of proteomic analysis to find potential diagnostic biomarkers is limited by the presence of serum albumin (HSA) and immunoglobulin (IgG) at high concentrations in patients’ blood; these substances impede the detection of serum proteins with similar molecular weights. Recombinant HSA- and IgG-binding polypeptides are used as ligands in creating sorbents for complete removal of the proteins by affinity chromatography. The binding specificity of the sorbents for HSA and IgG is higher than that of the conventionally used antibodies. A composite sorbent enabling the depletion of HSA and IgG from serum by single-step affinity chromatography was obtained. The developed sorbents were used to prepare serum for proteomic analysis.     

Chromatography of carboxylic proteinases on sorbents containing the 2,4-dinitrophenyl group. Role of ionic interactions]

The chromatography of porcine pepsin on biospecific sorbents (Sepharose-4B-epsilon-DNP-aminocapronylhydrazide and Sepharose-4B-N-DNP-N'-acetylhexamethylenediamine) was studied. The sorbents in question differ from the previously used hydrophobic sorbent Sepharose-4B-DNP-hexamethylenediamine by the lack of strongly basic groups in the site of the ligand binding to the polymeric matrix. No qualitative differences in the pepsin chromatography on the three sorbents were observed. Presumably the decrease of the pepsin binding to the sorbents, containing the dinitrophenyl group, at pH values above the isoelectric point may be due to the effects of the salt on the binding site in the enzyme molecule rather than to the screening of the positive charges of the sorbent by chlorine ions. A commercial preparation of pepsin was purified 2-fold on the sorbent Sepharose-4B-epsilon-DNP-animocapronylhydrazide. The synthesis of sorbents is described.     

Sorbents with immobilized glycopeptide antibiotics for separating optical isomers by high-performance liquid chromatography

Chiral sorbents for HPLC separation of optical isomers carrying glycopeptide antibiotics (eremomycin or its eremosaminyl aglycon, ristomycin, or vancomycin) fixed onto the surface of silica gel have been synthesized. The patterns of the retention and separation of profen isomers and their dependence on the nature of the chiral selector and the eluant composition have been studied. The sorbents were shown to be highly enantiospecific in separating the isomers of alpha-amino-, alpha-hydroxy-, and alpha-methylphenylcarboxylic acids (profens).