Cell targeting by antibody-functionalized calcium phosphate nanoparticles

Calcium phosphate nanoparticles were coated with a shell of silica and covalently functionalized by silanization, either with thiol or with amino groups. This permits the covalent attachment of molecules like dyes or antibodies. Between the calcium phosphate surface and the outer silica shell, biomolecules like nucleic acids (DNA or siRNA) can be incorporated as cargo. This leads to cell-specific carriers of biomolecules into cells, e.g. for transfection, gene silencing or cell activation. The cellular uptake of antibody-coated calcium phosphate nanoparticles was demonstrated on two cell lines: He La (epithelial cell line) and MG-63 (osteoblast-like cell line). Furthermore, the functionalization of calcium phosphate nanoparticles with a dendritic cell-specific antibody (CD11c) led to a cell-specific targeting as shown with primary murine splenocytes. Thus, the successful coating of calcium phosphate nanoparticles with cell-specific antibodies makes them suitable for many clinical applications.