Objective To prepare semiconductor quantum dots（QDs）-Smad2 monoclonal antibody fluorescent probes, to detect the optical qualities and the ability to specific recognition of Smad2 in rat dental papillae cells（RDPC） of quantum dots-Smad2 monoclonal antibody fluorescent probes. Methods 1）QDs were chemically modified with Smad2 proteins to prepare water soluble QDs-Smad2 monoclonal antibody fluorescent probes which were purified after preparation. 2）The absorption band and emission band of these probes were obtained through ultraviolet spectrophotometer and fluorospectrophotometer, the shape, fluorescence intensity and photochemistry stability of these probes were studied through confocal laser scanning fluorescence microscopy. 3）Before the location of Smad2 proteins in RDPC was studied with anti -Smad2 immunocytochemical method and direct immunofluorescence imaging, RDPC were incubated with transforming growth factor-β1（TGF-β1）, and the related optical qualities of quantum dots-Smad2 monoclonal antibody fluorescent probes in RDPC were detected. Results QDs and monoclonal antibody linked together through covalent bond to form the fluorescent probes which could specifically and effectively recognize Smad2 proteins in RDPC. 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 link together through covalent bond to form the nanometer molecular probes with distinct optics character and photostability, which provides the scientific evidence that QDs can visualize the molecular movement in living cells in long-term, in situ and in real time.
