New use of cyanosilane coupling agent for direct binding of antibodies to silica supports. Physicochemical characterization of molecularly bioengineered layers.
A simple protocol to fix biological species to silica-based surfaces (silica microbeads and glass slides), using a bifunctional silane reagent (3-cyanopropyl dimethyl chlorosilane), is presented. This silane reagent was used without further derivatization. This system led to strong, but not covalent, linkage of antibodies through their glycosylated regions (OH groups) to solid supports. The use of a microsized sample revealed that the coupling process depends not only on physicochemical interactions but also on steric phenomena, and in this case, it was shown that a molecule acting as a spacer was required for more efficient cell fixation. Here, monoclonal mouse antibodies against the CD45 molecule expressed on rat lymphocytes (MAR anti CD45 Ab) were linked to lymphocytes, and as spacers, sheep anti-mouse antibodies (SAM Ab) were immobilized on silica surfaces, allowing the cells to stick to the floating hollow silica microbeads by simple incubation. Under such conditions, a single microbead can fix several cells. The potential of this hollow, low-density support is in ultrasound applications, for the destruction by cavitation phenomena of cells selectively fixed onto such a support. Such a study can serve as a basic model for various microbiosystems involving cell manipulation.