New use of cyanosilane coupling agent for direct binding of antibodies to silica supports. Physicochemical characterization of molecularly bioengineered layers

A simple protocol to fur biological species to silica-based surfaces (silic a microbeads and glass slides), using a bifunctional silane reagent (3-cyan opropyl 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 s olid supports. The use of a microsized sample revealed that the coupling pr ocess depends not only on physicochemical interactions but also on steric p henomena, and in this case, it was shown that a molecule acting as a spacer was required for more efficient cell fixation. Here, monoclonal mouse anti bodies against the CD45 molecule expressed on rat lymphocytes (MAR anti CD4 5 Ab) were linked to lymphocytes, and as spacers, sheep anti-mouse antibodi es (SAM Ab) were immobilized on silica surfaces, allowing the cells to stic k to the floating hollow silica microbeads by simple incubation. Under such conditions, a single microbead can fur several cells. The potential of thi s hollow, low-density support is in ultrasound applications, for the destru ction by cavitation phenomena of cells selectively fixed onto such a suppor t. Such a study can serve as a basic model for various microbiosystems invo lving cell manipulation.