OBJECTIVETo prepare semiconductor quantum dots (SQD)-Smad4 monoclonal antibody fluorescent probes and to detect the optical qualities and the ability of specific recognition of the probes.

METHODSSQD were chemically modified with Smad4 monoclonal antibody proteins to prepare water soluble probes, and the fluorescence intensity, photostability, absorption spectra and emission spectra of the probes were studied. The location of Smad4 in rat dental papillae cells (RDPC) was examined by SP anti-Smad4 immunocytochemical method and SQD-Smad4 direct immunofluorescent imaging.

RESULTSSQD and monoclonal antibody covalently bonded to form the fluorescent probes which could specifically recognize Smad4 in RDPC. These fluorescent probes still had properties, including broad absorption band, narrow emission band, high fluorescence intensity and photostability.

CONCLUSIONSSQD and monoclonal antibody could covalently bond to form the fluorescent probes with distinct optics character and ability of specific recognization, which provides the scientific evidence that SQD trace the molecular movement in living cells in long-term, in situ and in real time.