Synthesis and properties of polymeric latex particles and their conjugates with human immunoglobulin G

Synthesis and Characterization of Polystyrene Core/Polyacrolein Shell Latexes

The poly(styrene/acrolein) latexes were synthesized in an emul sifier-free emulsion-precipitation polymerization. Monodisperse particles from 0.30 μm to 0.52 μm, depending on the acrolein monomer feed, were obtained. More acrolein in the monomer feed yielded latex particles with smaller di ameters. Analyses indicate that the particles have a core-shell morphology. The core is rich in the hydrophobic (polystyrene) component whereas the shell is composed mainly of hydrophilic polyacrolein. Significant changes in polyacro lein in the latexes (from 0.03 to 0.28) has less influence on the composition of the shell (from 0.5 to 0.84, respectively). The surface of the latex particles is smooth and can be penetrated by 2,4-dinitrophenyl hydrazine to the depth from 1.5 to 3.5 Å. These poly(styrene/acrolein) latexes are capable of binding ca. 3 mg of human globulins or ca. 1 mg of human serum albumin on 1 m2 of the latex surface.

Electrophoretic Properties of Latex Particles with Immobilized Bovine Serum Albumin

In this study, bovine serum albumin (BSA) was covalently immobilized onto the surfaces of methyl methacrylate/methyl acrylic acid core-shell latex particles by the carbodiimide method, and the variation of the zeta potential of the BSA-latex complex as a function of the amount of BSA immobilized was measured. The experimental data revealed that the absolute zeta potential of BSA-latex complex exhibited a local minimum at 0.05 mg/m(2) of immobilized BSA. A two-layer model for the description of the electrophoretic behavior of the BSA-latex complex is proposed which is capable of explaining the behavior of the variation of the zeta potential as a function of the amount of BSA immobilized. Copyright 2001 Academic Press.

Adsorption and covalent immobilization of human serum albumin (HSA) and gamma globulins (gamma G) onto poly(styrene/acrolein) latexes with pyrene, dansyl, and 2,4-dinitrophenyl labels

The poly(styrene/acrolein) latexes (P(SA)1 and P(SA)2), differing in poly(acrolein) content, were synthesized by the emulsifier-less emulsion-precipitation polymerization of styrene and acrolein. The fraction of poly(acrolein) in the surface layer was 0.35 and 0.50, for the P(SA)1 and P(SA)2 latex, respectively. Latexes were labelled with 2,4-dinitrophenylhydrazine (DNPH), dansylhdrazine (DAH), and 1-aminopyrene (APY). Surface concentration of labels varied from 4.20.10(-7) mol m-2 (for APY label on P(SA)1 latex) to 1.54.10(-6) mol m-2 (for DNPH label on P(SA)2 latex) reflecting the fraction of polyacrolein in the surface layer and bulkiness of the label. The differences between adsorption and covalent immobilization of human serum albumin and gamma globulins onto the P(SA)2 latex and onto its derivatives labelled with the 2,4-dinitrophenyl (DNP), dansyl (DA), and pyrene (PY) groups were small. The observation conforms to the hypothesis that polyacrolein forms domains on the surface of the P(SA) latexes and that after labelling some aldehyde groups are still available for the covalent immobilization of proteins. Labelled and parent latexes were used in the model slide and turbidimetric aggregation tests for the goat anti-HSA. The fluorescent latexes, labelled with APY and DAH, and latexes labelled and with DNPH were found to be suitable for the model tests, similarly as the nonlabelled ones, however, some differences in the sensitivity, depending on the presence and the nature of labels, were noticed. The standard goat anti-HSA serum (Sigma) was detected at maximum dilution equal to 2000 in the slide test, and in the dilution region from 1.8.10(3) to 4.7.10(6) times in the turbidimetric test.

Composite poly(methyl methacrylate-methacrylic acid-2-hydroxyethyl methacrylate) latex for immunoassay. The case of plasminogen

Poly(methyl methacrylate-methacrylic acid-2-hydroxyethyl methacrylate) latex (ACRYLAT) was synthesized by radical precipitation polymerization. The mass median diameter (MMD) and the geometrical standard deviation (GSD) of the ACRYLAT particles were 138 nm and 1.2, respectively. The concentration of the titrable carboxylic groups in the surface layer of latex particles was equal to 8.41 x 10(-6) mol m-2. Latex was able to bind up to 2.82 x 10(-7) mol of 1-aminopyrene per 1 m2 of the surface of the latex particles due to the ionic interactions between carboxylate anions and ammonium cations of protonated 1-aminopyrene. ACRYLAT was able to immobilize covalently human serum albumin in amounts up to 0.23 mg m-2. Aggregation of ACRYLAT with immobilized HSA, induced with specific antibodies (anti-HSA), was investigated turbidimetrically. The results indicated that in the model turbidimetric immunoassay, ACRYLAT coated with HSA can be used for the detection of anti-HSA in the goat anti-HSA serum diluted from 50 to 7000-fold. Immobilization of rabbit antibodies to plasminogen (anti-Plg) to ACRYLAT via the epsilon-aminocaproic acid linkers provided particles which were used for the development of the turbidimetric immunoassay for plasminogen. In this assay plasminogen could be detected in concentration ranging from 0.75 to 75 micrograms ml-1 in the blood plasma.

Fundamental study on latex reagents for agglutination tests

Competitive adsorption of Fab and Fc fragments on to particles revealed that the main driving forces for the adsorption of Fab and Fc fragments are ionic and hydrophobic forces, respectively. Latex particles were sensitized with antihuman C-reactive protein-antibody under a condition where ionic binding force was suppressed, and hence antibody was supposed to attach to the particles predominantly at the Fc site. The resulting latex indicated a high efficiency for the determination of C-reactive protein. Among the latexes used, a partially hydrolysed styrene-acrylamide copolymer latex was the best with respect to test efficiency and storage stability.

Direct examination of chemical kinetic laws by visual imagery. IV. Association processes between antigen- and fragmented antibody carrying fluorescent latex particles

The binary association process was further examined by direct visual observation using a fluorescence microscope connected to an image-processing system and by a spectrophotometric method. In the present paper, we used human serum albumin (HSA)- and fragmented anti-HSA antibody-carrying fluorescent latex particles in order to attain higher sensitivities and exclude complexities that might be caused by dissociation of the association product. The rate constant of the binary association process was estimated to be 6.0 x 10(8) M-1 s-1 at 30 degrees C and pH 7.6. The activation parameters of the association process were evaluated. The effects of pH and viscosity of the suspension on the association process were also examined.

Preparation of microspheres of poly(glycidyl methacrylate) and its derivatives as carriers for immobilized proteins

Microspheres of poly(glycidyl methacrylate) and its derivatives have been prepared. The diameter can be varied in the range from 0.5 to 5 micron. Proteins were immobilized on the microspheres by various processes. The maximum amount of covalently immobilized gamma-globulin on the microspheres was found to be about 6 mg/m2. It was shown that dyed microspheres with a diameter of 2-4 micron are applicable to immunological agglutination tests on a microplate as carrier particles substituting for red blood cells.