Abstract: CHEN Xiao-gang, ZHANG Zhen, FEI Ye, CHEN Xiang-dong*. *Shanghai Ninth People′s Hospital, Shanghai Jiao Tong University, Shanghai 200011, China Corresponding author: CHEN Xiang-dong, Email: xdchen@medmail.com.cn 【Abstract】 Objective To prepare arginine-glycine-aspartic acid （RGD）- and ribonuclease A （RNase A）-conjugated CdTe quantum dot （QD） nanoprobes, and to observe their capability to target human A375 malignant melanoma cells. Methods RNase A-modified CdTe quantum dots （CdTe RQDs） were obtained by using a microwave-based heating method, and then chemically conjugated to the RGD peptide to prepare RGD-CdTe RQD nanoprobes, which were then physically and chemically characterized by transmission electron microscopy, powder crystal diffraction, fluorescence spectrophotometry, and ultraviolet absorption spectrophotometry. A375 cells were cultured in vitro and incubated with various concentrations （20, 40, 80 nmol/L） of RGD-CdTe RQD nanoprobes for different durations （12, 24, 36, 72 hours）. Then, methyl thiazolyl tetrazolium （MTT） assay was conducted to estimate the proliferative activity of A375 cells. To observe the targeting capability of RGD-CdTe RQD nanoprobes, A375 cells were treated with RGD-CdTe RQD nanoprobes at the concentration determined by MTT assay for one hour followed by laser confocal microscopy. Results CdTe RQDs with good dispersion and biocompatibility were obtained by using a microwave-based heating method, and then successfully conjugated to the RGD peptide to form RGD-CdTe RQD nanoprobes. The treatment with RGD-CdTe RQDs of 20 nmol/L for 12 hours exhibited the weakest effect on the proliferative activity of A375 cells, and hence, 20 nmol/L was selected for the fluorescence imaging assay. Laser confocal microscopy revealed that RGD-CdTe RQD nanoprobes were able to actively target A375 cells. Conclusion RGD-CdTe RQD nanoprobes with a favorable capability to actively target A375 cells are successfully prepared in this study. 【Key words】 Melanoma; Quantum dots; Molecular probes; Protein transport; RGD

Key words: melanoma, Quantum dots