Synthesis of molybdenum oxide quantum dots with better dispersity and bio-imaging ability by reduction method

Abstract A reduction method was proposed to synthesize better dispersed molybdenum oxide quantum dots (MoOx QDs) with stable fluorescence properties by using molybdenum disulfide (MoS2) and hydrogen peroxide (H2O2) as precursor and oxidant, and using ethanol as reducing agent and surfactant of oleylamine as modified agent. The morphology of the as-prepared MoOx QDs with average size of 1.96 nm were observed, calculated and analyzed from TEM and AFM detections. Excitation-dependent photoluminescence emission of MoOx QDs could be obtained and MoOx QDs exhibited blue fluorescence under UV light irradiation. Factors that influenced the syntheses of MoOx QDs were discussed, and the highest value of fluorescence intensity was exhibited with the adding of 5 mL oleylamine and the reaction time of 24 h. The cell imaging behaviors, the physiological stabilities and in vitro cytotoxicity testing of MoOx QDs were further discussed with HeLa cells as model. And the results showed that it might be a promising biomedical material as high quality fluorescent probes for bio-imaging.