Functionalization of magnetic colloidal particles for bioanalytical applications

Abstract

A key trend in the current bioanalytical developments is the use of highly dispersed particles serving as carriers for reagents that bind the detected analytes and generators of signals from the analyte-containing complexes. Magnetic colloidal particles (MCPs) successfully implement the first function. Binding of analyte with receptors on the MCPs surface, separation of the MCPs from the reaction medium using a magnetic field and subsequent resuspension allow simple and rapid concentration of the analyte and elimination of matrix components. To integrate these advantages into highly sensitive assays with optical detection, the MCPs should be functionalized with intensely colored components. In the presented work, the use of gold nanoparticles (GNPs) and organic dyes for this purpose was investigated.
MCPs synthesized by reducing iron salts were stabilized with silicon derivatives to form porous organic frameworks on which GNP cores were adsorbed and further grown by reducing gold salts. For covalent immobilization of dyes, MCPs coated with a stabilizing polymer with carboxyl groups were used. Of the dyes studied, magdal red provided the highest intensification of coloration while maintaining MCPs' stability. The obtained particles were tested by transmission electron microscopy and dynamic light scattering. Protocols of their functionalization by antibodies were comparatively considered. Finally the preparations were tested for their movement and antigen-binding properties in systems of lateral flow immunoassays. The chosen preparations have diameters in the range 300-500 nm for gold functionalization and 200-600 nm for the colorant's use.
The study is financially supported by the Russian Science Foundation (grant 24-23-00523).

Speaker

Nadezhda A. Taranova
A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences
Russia

Discussion

Ask question