发绿色荧光碳点的制备并用于Pb2+的灵敏检测和细胞成像

Preparation of carbon dots with green fluorescence for highly sensitive detection for lead ions and cell imaging

碳点作为一种新型的荧光纳米材料,与传统的半导体量子点相比具有优异的生物相容性、低毒性、易修饰等优点,使其在生物医学领域具有广泛的应用前景。本文以L-半胱氨酸和蔗糖为原料,在0.1 mol·L^-1的NaOH溶液中成功的制备出发绿色荧光的碳点(G-CDs),最佳发射波长是515 nm,经表征得出其表面主要还有氨基、羟基和羧基等基团,荧光量子产率高达33.4%,其荧光可被Pb^2+特异性猝灭,最终应用于Pb^2+的灵敏检测,检出限为0.025μmol·L^-1。经MTT法测定G-CDs对人肝癌细胞(SMMC-7721)为低毒性,最后应用到细胞荧光成像中,通过细胞成像技术成功检测细胞中Pb^2+的存在。

As a new type of fluorescent nanomaterial,carbon dot has excellent biocompatibility,low toxicity and easy modification compared with traditional semiconductor quantum dots,which has broad application prospects in biomedical field.In this paper,L-cysteine and sucrose are used as raw materials to prepare green fluorescent carbon dots(G-CDs)in 0.1mol·L^-1 NaOH solution,its optimal emission wavelength is 515 nm.There are mainly amino,hydroxyl and carboxyl groups on the surface of G-CDs.The as-prepared carbon dots display strong fluorescence with a quantum yield of 33.4%,which can be specifically quenched by Pb^2+,and finally apply to the sensitive detection of Pb^2+with a detection limit of 0.025μmol·L^-1.The MTT assay is used to determine the low toxicity of G-CDs on human hepatoma cells(SMMC-7721).Finally,it is applied to fluorescence imaging of cells,and the presence of Pb^2+in cells is successfully detected by a laser scanning confocal microscope.