Folic acid as delivery vehicles: targeting folate conjugated fluorescent nanoparticles to tumors imaging.

Herein, folic acid (FA) conjugated with AuNPs were introduced into the cancer cell imaging via the specific interaction between FA and the folate receptor on the cell surface. FA protected gold nanoparticles (AuNPs) was synthesized and labeled with fluorescein isothiocynate (FITC) to form the FITC-FA-AuNPs (FFANPs). As over-expressed folic acid receptor in some cancer cells and folic acid can specifically and selectively combine, the FFANPs can bind to the FR expressed on tumor cells such as HeLa cells (human epithelial cervical cancer) and CERF-CEM cells (T cell line, human acute lymphoblastic leukemia). As a result, cancer cell imaging can be achieved. To ascertain the FR target ability, it has been acquired by FR-targeted images using synthetic FFANPs. The formation of FITC-FA can be identified by MS. FCM was carried out to study the cell uptake of FFANPs. The cell toxicity (3-[4,5-dimethylthiazolyl-2]-2, 5-diphenyltetrazolium bromide, MTT) assay demonstrated that the FITC-labeled conjugate had only little effect on the cytotoxicity to the cells, which further proved the applicability of the method in tumor cell imaging.