Spectrofluorimetric cytosensing of colorectal cancer cells using terbium-doped dendritic fibrous nano-silica functionalized by folic acid: A novel optical cytosensor for cancer detection.

A novel fluorescent probe for detection of HT 29 cancer cells was developed based on terbium-doped dendritic fibrous nanosilica functionalized by folic acid (Tb@KCC-1-NH2-FA). Using this probe, fluorescence signals was emitted by Tb@KCC-1-NH2-FA at 490 nm by applying 380 nm as excitation wavelength. The reported probe is based on the interaction between FA decorated on the surface of Tb@KCC-1-NH2-FA and folate receptor (FR) which is overexpressed on the surface of the most of cancer cells. Fluorescence microscopy and flow cytometry were utilized to verify the uptake of Tb@KCC-1-NH2-FA with FR-positive HT 29 cancer cells. The specificity of Tb@KCC-1-NH2-FA towards FR-positive cells was approved by staining HEK 293 cells as FR-negative cells with Tb@KCC-1-NH2-FA which obtained results approved selective differentiation of normal cells with the FA-decorated nanomaterials. The cytotoxicity of Tb@KCC-1-NH2-FA was evaluated by MTT assay which confirmed their biocompatible nature. Under optimum conditions, this cytosensor is able to detect HT 29 colon cancer from 500 to 6.5 × 103 cells/mL with lower limit of detection (LLOQ) of 500 cells/mL. Due to the room temperature stability of Tb@KCC-1-NH2-FA, this cytosensor could be developed in a simple way with exceptional specificity which may show potential applications for early stage detection of colon cancer.