Mesoporous silica-coated quantum dots functionalized with folic acid for lung cancer cell imaging

The monitoring of folate receptor levels in living cancer cells has attracted increasing interest; however, the present fluorescent probes used often suffer from interference from nonspecific adsorption on the surface of non-target cells. In the present study, the probe is readily prepared by using folic acid as a template molecule, a mesoporous silica nanoparticle as an imprinting material, and a CdTe quantum dot as a signal transducer for the recognition of folate receptors. This system is expected to offer specific recognition of folate receptors over other substances based on the high affinity of folic acid and folate receptors. The probe is stable and monodispersed in an aqueous suspension, and has little toxicity to living cells and thus can be utilized for targeted A549 cell imaging. The living cell imaging experiments further demonstrate its value in bioimaging cell-surface folate receptors by virtue of its superior biocompatibility, lower cytotoxicity and membrane permeability.