Stem cells nanotechnology has emerged as a new exciting area, and holds great potential for research and development of stem cells as novel therapeutic platforms for genetic, traumatic, and degenerative medicine. Vital to the success of this technology are approaches that reproducibly facilitate in vivo cell tracking, expansion, differentiation, and transplantation. Herein we reported the effects of CdSe/ZnS quantum dots covered multi-walled carbon nanotubes (FMNTs) on mice embryonic stem cell line CCE cells. The FMNTs were prepared by plasma surface treatment and characterized by high resolution transmission electron microscopy (HR-TEM), and incubated with murine ES CCE cells for 1 to 28 day.These ES cells were observed by confocal laser scanning microscopy, and were analyzed by real time reverse transcription-polymerase chain reaction (RTPCR), flow cytometry (FCM) and MTT method. Results showed that prepared FMNTs exhibited green fluorescent signal, could enter into ES cells in time-dependent means, more than 20 µg ml^-1 FMNTs induced ES cells become smaller and smaller as the incubation time increased, and inhibited cell growth in dose-and time-dependent means, induced apoptosis of ES cells; conversely, 5 µg ml^-1 FMNTs could markedly stimulate the expression of Sox1 and Hsp27, and inhibit expression of OCT4 in ES cells, FCM analysis showed that differentiation marker Flk-1 exhibited higher expression compared with control ES cells. In conclusion, high dose of FMNTs can inhibit proliferation of ES cells, low dose of FMNTs can improve the differentiation of ES cells, FMNTs can have potential applications in in vivo tracking, imaging and regulation of the proliferation and differentiation of ES cells.

A ultra-sensitive, highly specific, real-time polymerase chain reaction system based on mercaptoacetic acid-modified CdTe nanocrystals(mQDs) is reported. With the addition of 3 nm mQDs into the PCR reagent, the photoluminescent(PL) intensities of mQDs decreased gradually as the DNA templates and PCR cycles increased, in an approximate negative linear relation to the DNA concentration logarithm or cycles, the PL peaks exhibited red-shifts synchronously. Mg²⁺ ions decreased the PL intensity of mQDs in a dose-dependent means, and Taq DNA polymerase enhanced the PL intensity of mQDs in a dose-dependent means. Real-time PCR based on mQDs showed an increased sensitivity at least 103 fold higher than that based on SYBR Green I. The specificity of PCR was enhanced in the PCR reagent with less than 1.33mg/mL mQDs. The potential mechanism is also discussed. This novel PCR system based on mQDs has great potential in applications such as ultra-sensitive specific DNA or RNA detection, dynamic molecular imaging, and photoelectric biosensors.