Objective:To prepare semiconductor quantum dots (QDs)-Smad4 monoclonal antibody Fluorescent probes

and to detect nucleation shifting process of Smad4 signal protein in Rat dental papillae cells(RDPCs) stimulated by TGF-β1 with the Fluorescent probes. Methods:①QDs were chemically modified with Smad4 proteins to prepare water soluble QDs-Smad4 monoclonal antibody Fluorescent probes which were purified after the preparation. ②The properties of these probes were studied through absorption band analyses

fluorescence spectra

fluorescence spectrum analyses and confocal laser scanning fluorescence microscopy. ③The location of Smad4 proteins in RDPCs was studied with SP anti-Smad4 immunocytochemical method

QDs direct mark method

Smad4 monoclonal antibody direct mark method

and direct immunofluorescence imaging.And the properties of Quantum Dots-Smad4 monoclonal antibody Fluorescent probes in RDPCs were detected. ④After RDPCs ware cultivated by TGF-β1 for 0 hours

12 hours

and 14 hours

the dynamic nucleation shifting process of Smad4 signal protein in RDPCs was separately detected with SP anti-Smad4 immunocytochemical method and direct immunofluorescence imaging.Results:QDs and monoclonal antibody ware covalently bonded to form the fluorescent probes which could specifically and effectively recognize Smad4 proteins in RDPCs .It is to demonstrate the dynamic nucleation shifting process of Smad4 signal protein in RDPCs. These Fluorescent probes still had good properties

including broad excite spectra

narrow emission spectra

high fluorescence intensity

and photostability. Conclusion:QDs and monoclonal antibody could be covalently bonded to form the fluorescent probes with distinct optics character

special immunity recognition capability and the ability of imaging mark the protein in cells for long time

which provides the scientific evidence that QDs can visually research the movement and interaction of protein in living cell .