Mamed Mustafaev

The polymerization of acrylamide initiated with CE(IV) and KMNO4 redox systems in the presence of glycine

Glycine-Ce(IV) salts and -KMnO 4 initiator systems were used for the polymerization of acrylamide, resulting in water-soluble polyacrylamide, which contains amino acid end groups. The dependence of polymerization yields and molecular weights of polymers on the mole ratio of acrylamide monomer to glycine, the polymerization time, the temperature, and the concentration of sulfuric acid were investigated. The decrease in the mole ratio of acrylamide to glycine resulted in a decrease in the molecular weight, and an increase in the yield of acrylamide polymer, which contains a glycine end group. With increasing acid concentration of the polymeric solution, the polymerization yield and the molecular weight of polymer decrease. Ce(IV) and Mn(IV) reduced to Ce(III) and Mn(II) in the polymerization reaction. The amounts of Ce(III) and Mn(II) bound to polymer were determined. The composition of the polymerization product was investigated and a bimodal character of the molecular weight distribution was observed. The mechanism of this phenomena is discussed.

Water-soluble polypyrroles by matrix polymerization : Interpolymer complexes

A new class of water-soluble polypyrroles (PPy) has been developed. This was accomplished by oxidative matrix polymerization of pyrrole (Py) monomer with Ce(IV) in the presence of poly(acrylic acid (PAA), poly(vinyl pyrrolidone) (PVP), and copolymers (CP) of vinyl pyrrolidone(VP) with acrylic acid (AA) [VP/AA; 25/75 ( CP 1 ), 50/50 ( CP 2 ), 75/25 ( CP 3 )]. The soluble and insoluble interpolymer complexes were observed according to the nature ( and conformation ) of polymers in mixture, the ratio of components, and the pH of solutions. The role of PAA, PVP, CP, Py, and Ce(IV) concentrations, the order of component addition, and the pH of the solutions were investigated. The evidence and structural reasons for the formation of soluble interpolymer complexes of PPy with different polymers are discussed. It is proposed that the compactization of the polymer matrix as well as the disturbance of the regularity of reactive groups on the polymer chain decreases the possibility of formation of soluble interpolymer complexes.

Cu2+-mediated complex formation between polyacrylic acid (PAA) and bovine serum albumin

Cu(2+)-mediated complex formation between polyacrylic acid (PAA) and negatively charged bovine serum albumin (BSA) was studied in neutral water in the presence of Cu2+. Depending on the concentration of Cu2+, the reaction between PAA-Cu2+ complexes and BSA appeared to follow one of two possible paths. At low Cu2+ concentrations (nCu/nAA 0.15), a further increase in BSA concentration led to the formation of non-stoichiometric polycomplexes (mechanism II): [formula: see text] The immunogenic properties of ternary mixtures of BSA-Cu(2+)-PAA were investigated and the relationship between immunogenicity and complex formation in solution was analyzed. The addition of Cu2+ to solutions of PAA with BSA gave rise to a considerable increase in BSA-specific immunogenicity. Data obtained from the analysis of the immunogenicity of BSA-Cu(2+)-PAA mixtures formed using different ratios of the components suggested that (1) the highest immunogenic activity is exhibited by stable ternary complexs, and (2) immunoactive polyelectrolyte complexes have a non-stoichiometric composition. We thus propose a novel method, based on Cu2+ mediated complex formation, to enhance protein-specific antibody responses.

New amphiphilic immunogens by Cu2+-mediated complexes of water-born poly(N-isopropylacrylamide) and bovine serum albumin

Cu2+-mediated complex formation between temperature-responsive poly(N-isopropylacylamide-co-acrylic acid) (CP) and bovine serum albumin (BSA) was investigated in neutral and in physiological salt solutions. Water soluble or insoluble ternary complexes are formed upon addition of divalent copper ions to the solution. Stability of the ternary polycomplexes depends on the composition of the copolymers, concentration of copper ions and ratio of components. Stimuli-sensitive (temperature, pH- and ionic strength-) behavior of CP, CP-Cu2+ and CP-Cu2+-BSA solution was studied. The ternary CP-Cu2+-BSA complexes exhibit reversible temperature-responses in physiological salt solutions at suitable ratios of the components. Thermal collapse of ternary polycomplexes was observed in higher pH solutions than for CP and CP-Cu2+. The negative temperature solubility coefficient in salt containing solutions may be due to cooperative hydrophobic interactions. Cu2+ in 0.154 M NaCl solutions of CP with BSA, in contrast to CP-Cu2+ BSA complexes in water, gave increased BSA-specific immunogenicity. A single immunization of mice with ternary CP1-Cu2+-BSA complexes in physiological salt solutions without adjuvant increased the specific immune response to BSA. The highest level of immunogenic activity was after a second immunization which lasted more than 18 months. The highest immunogenic activity was exhibited by stable ternary complexes, and immunoactive polycomplexes with a negative temperature solubility coefficient. A hypothetical structural model for the formation of ternary polycomplexes and mechanism for the manifestation of immunological activity are presented.

New amphiphilic immunogens by poly(N-Isopropylacrylamide)-modified bovine serum albumin

Abstract Using poly (N-isopropylacrylamide) co-oligomer with N, N-dimethylacrylamide (DMAAm) (IDc) we prepared polymer-protein conjugates of bovine serum albumin (IDc-BSA). The conjugate underwent reversible hydration-dehydration changes in response to temperature changes and revealed phase separation at body temperature. Mice were immunized by the intravenous, intramuscular or intradermal routes with the IDc-BSA. The intravenous route of single immunization without adjuvants evoked increased primary and secondary specific immune responses to IDc-BSA, whereas the intramuscular and intradermal did not elicit higher antibody production. The intradermal administration of BSA and IDc-BSA together with IFA both gave rise to high immunological activity. It is suggested that the Hydrophobic chain aggregation site of the IDc-BSA conjugate at body temperature would increase the adsorptive capacity of BSA on the immunocompetent cells. The efficiency of such “forced” interactions of conjugate aggregates (high epitope density) are high enough for the immune response.

Immune response to progesterone involved in Cu2+-mediated polyanion-protein complex — antigen specificity and affinity of hybridoma clones

The immunogenic properties of water soluble (PAA-Cu(2+)-BSA) and colloidal (PAA-Cu(2+)-BSA.P) polycomplexes were investigated, and the specificity of antibodies produced was analyzed. Polycomplexes containing progesterone appeared to possess a high steroid-specific immunogenic activity. A comparative study of immunogenic properties of polycomplexes versus BSA.P + incomplete Freunds adjuvant (IFA) mixtures revealed differences in regards to the specificity of antibody production. In contrast to the IFA system, polycomplexes were able to generate P- as well as BSA-specific antibodies. Such a response is determined, possibly, by increases in the immunogenicity of weak antigenic determinants on the surface of protein globules and or by the representation of dormant determinants existing in the miner site upon complex formation with polyelectrolytes. Finally, using a short immunization procedure based on use of PAA-Cu(2+)-BSA polycomplexes, we produced seven monoclonal antibodies against progesterone included in polyelectrolyte complexes with affinities Kd ranging between 1.3 x 10 (-5) and 9 x 10(-8) M.

Immune Response to 17β-Estradiol Involved in Polymer Gels: Antigen Specificity and Affinity of Hybridoma Clones

The immunogenic properties of 17beta-estradiol, immobilized in negatively charged polymer gels, were investigated, and the specificity of antibodies produced was analyzed. The polymer gels developed were composed of a hydrophobic estradiol core surrounded by hydrophilic polyanions as corona. As an immunogen, it was conceived to function via a dual mode, that is as a hapten-delivery system (prolongation effect) and as a polyelectrolyte adjuvant. Polymer gels containing estradiol appeared to possess a high estradiol-specific immunogenicity even without the addition of traditional adjuvants. A comparative study of estradiol trapped in polymer gels versus estradiol conjugated to bovine serum albumin (BSA.E) + Incomplete Freunds Adjuvant (IFA) mixtures revealed similar immunogenic properties in terms of induction of specific antibodies. Following a short immunization procedure based on the use of 17beta-estradiol immobilized in polymer gels, we developed 10 specific monoclonal antibodies with Kd values ranging between 1.2 X 10(-7) and 8 X 10(-8) M.

Soluble and insoluble ternary complexes of serum proteins with polyanions in the presence of Cu2+ in water

Complex formation between polyacrylic acid (PAA) and bovine serum albumin (BSA), human serum albumin (HSA), hemoglobin (Hb), globin (Gl), and, respectively, transferrin (Tr), were studied in neutral water. Water-soluble and insoluble complexes are formed upon addition of divalent copper ions to the solution. The contacts between proteins and PAA are achieved via chelate unit formation in which the copper ions are located at the center. The solubility of the polycomplexes depends on the nature of proteins and correlates with their isoelectric points (pI). In the mixtures of Hb–Cu2+–PAA and Gl–Cu2+–PAA, insoluble complexes are formed at pH = pI starting with very low concentrations of Cu2+ (ncu/nAA ≤ 0.01). On the other hand, these polycomplexes remain soluble at pH > pI. BSA, HSA, and Tr form soluble ternary polycomplexes at neutral water (pH 7). The formation of the polycomplexes in the mixture BSA&–Cu2+–PAA was intensively studied by titration, HPLC, electrophoretic, and spectrophotometric methods. The solubility, composition, and stability of these polycomplexes depend on metal/polymer and protein/polymer ratio. Insoluble polycomplexes are formed when concentration of Cu2+ reaches a critical value (nCu/nAA ≥ 0.25). At this concentration of Cu2+, phase separation takes place, starting with very low concentration of protein in the system. Over the critical ratio of the protein/polymer, the mixture again exhibits water-soluble character. The pattern of distribution of Cu2+ between PAA coils and of protein globules between polymer-metal complex particules appeared to follow the self-assembly principle. A hypothetical structural scheme for the formation of soluble and insoluble ternary polycomplexes is proposed.

Fluorescence and Turbidimetry Study of Complexation of Human Serum Albumin with Polycations

Complexation of poly(N-ethyl-4-vinylpyridinium bromide) (PEVP) and poly(N-ethyl/cethyl-4-vinylpyridinium bromide) (PECVP) with human serum albumin (HSA) was studied by fluorescence spectroscopy and turbidimetric titration in dilute aqueous solutions. Solubility of polycation-HSA complexes depends on the initial concentrations and ratios of the components, pH, hydrophobic-hydrophilic balance of the macromolecules, and existence of low molecular salt (NaCl). A soluble interpolymer complex which is formed at low concentrations of polycation is insoluble at high polycation concentrations. The average fluorescence quantum yield of HSA decreases as polycation binds to the protein. The maximum reduction in emission intensity of HSA indicates the number of the HSA molecules bound per polymer chain. Quenching of HSA fluorescence by PECVP is decreased in the presence of NaCl at pH 7.0 but not at pH 4.3.