Amino‐functionalized latex particles obtained by a multistep method: Development of a new immunoreagent

Abstract

Cationic latex particles with surface amino groups were prepared by a multistep batch emulsion polymerization. In the first one, two or three steps, monodisperse cationic latex particles to be used as the seed were synthesized. In the third and fourth steps, the amino-functionalized monomer aminoethylmethacrylate hydrochloride was used to synthesize the final functionalized latex particles. Three different azo initiators 2,2Ј-azobisisobutyramidine dihydrochloride, 2,2Ј-azobisdimethylenisobutyramidine dihydrochloride, and 2,2Ј-azobisisobutyronitrile were used as initiators. Hexadecyltrimethylammonium bromide was the emulsifier. To characterize the final latices, conversions were obtained gravimetrically, and particle size distributions and average particle diameters were determined by transmission electron microscopy and photon correlation spectroscopy. The amount of amino groups was determined by conductimetric titrations. Colloidal aspects were ascertained by measuring the electrophoretic mobilities. Activation of these particles with glutaraldehyde produced an efficient reagent for latex-enhanced immunoassay. The covalent coupling efficiency (protein covalently bound with respect to the total amount of protein adsorbed) was compressed between 50 and 80%. The developed immunoreagent was applied to the measurement of serum ferritin concentration in a new turbidimetric procedure that was compared with a commercial nephelometric method; the results obtained with both methods demonstrated that the two procedures correlated well (r ϭ 0.992).

Evolution in Malaria Disease Detection: From Parasite Visualization to Colloidal‐Based Rapid Diagnostic

“…Recently, a variety of new latex particles potentially suitable for LAT have been synthesized, and emulsion polymerization has proved to be the most appropriate technique to tailor the particles with required characteristics (46)(47)(48)(49). For diagnostic test, the monodisperse particles are required to provide simultaneous latex agglutination.…”

Modeling the emulsion polymerization of amino-functionalized latex particles

“…The use of amino-functionalized particles has several advantages over other functionalities (the binding agent, glutaraldehyde, is more stable than carbodiimide; it can be used to form spacer arms and allows a good antibody orientation) [1,2]. In order to use this kind of particles in immunoassays, monodisperse, stable particles, of known surface amino group density are required.…”

Immunodiagnosis of Chagas disease: Synthesis of three latex–protein complexes containing different antigens of Trypanosoma cruzi

“…Immunodiagnosis tests involve specific reactions between an antigen (or antibody) contained in a human fluid and an antibody (or antigen) contained in the latex-protein complex. The particles agglutination process can be visualized either directly or via instrumental methods [1][2][3][4][5][6][7][8].…”