Cytotoxicity and cancer detection ability of the luminescent nanoporous silica spheres immobilized with folic acid derivative

Luminescent europium(III)-doped nanoporous silica spheres (Eu:NPS) were synthesized, and folic acid derivative (FA: folate N-hydroxysuccinimidyl ester) as targeting ligand for cancer cells was immobilized on the sphere through a mediation of 3-aminopropyltriethoxysilane (APTES). The ordered nanopores were preserved with the immobilization. The surface area decreased only with the APTES immobilization, suggesting that the FA was immobilized only on the outer surface of the nanopores. The photoluminescence of the spheres showed the characteristic peak due to interactions between the FA and Eu3+, and further the luminescence can be clearly detected by a fluorescent microscopy. The spheres were highly dispersed stability in cell culture medium to exhibit the nontoxic in the proliferation stage of Hela cancer cells and NIH3T3 fibroblasts, and specifically bindto the Hela cells. The binding and uptake spheres showed the intense luminescence. Thus, the luminescent FA-immobilized Eu:NPS spheres will exhibit the targeting and imaging abilities for cancer cells.