Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (20): 2169-2172.DOI: 10.6023/A12060302 Previous Articles     Next Articles



谢文菁, 傅英懿, 马红, 张沫, 范楼珍   

  1. 北京师范大学化学学院 北京 100875
  • 投稿日期:2012-06-23 发布日期:2012-08-27
  • 通讯作者: 范楼珍
  • 基金资助:

    项目受国家自然科学基金(No. 21073018, 21233003)和中央高校基本科研业务费专项资金资助.

Preparation of Fluorescent Graphene Quantum Dots as Biological Imaging Marker for Cells

Xie Wenjing, Fu Yingyi, Ma Hong, Zhang Mo, Fan Louzhen   

  1. Department of Chemistry, Beijing Normal University, Beijing 100875
  • Received:2012-06-23 Published:2012-08-27
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21073018, 21233003) and the Fundamental Research Funds for the Central University.

Currently, graphene has attracted much attention in the fields of bioimaging, biolabeling and drug delivery. Theoretical and experimental studies have shown that the graphene quantum dots (GQDs) are expected to show good optical properties due to their quantum confinement and edge effect. In this report, using the electrochemical assay the fluorescent GQDs with a diameter between 5 and 10 nm could be obtained via electrolysing graphite in alkaline condition and with hydrazine hydrate as a reducing agent at room temperature. The structure of the GQDs was confimed by means of transmission electron microscope (TEM) and atomic force microscope (AFM). The finding showed that the GQDs have an uniform size, and most of them are separate graphene. The GQDs mainly consist of single layer with less than 1 nm. Their features and properties were characterized by fourier transform infrared spectroscopy (FTIR), photoluminescence spectra (PL), UV-visible spectroscopy (UV-vis) and X-ray diffraction (XRD). The results indicated that the GQDs have bright yellow luminescence with a 14 % quantum yield, which is higher than that of traditional carbon quantum dots reported previously. When they were excited by different excitation wavelengths, the intensity of photoluminescence increased to the maximum, and then decreased gradually. The fluorescent emission peak of the GQDs remained unshifted, suggesting a novel kind of quantum dots different from those of graphene oxide quantum dots depending excitation wavelengths. The luminescence of GQDs arises from the graphene modified with the phthalhydrazide-like groups and hydrazide groups at the edge. The highly fluorescent GQDs have high water solubility, good photostability and biocompatibility, indicating that the GQDs can easily enter the cells. By incorporating the GQDs with A549 (lung cancer) and MCF-7 (breast cancer) cells through MTT assay, the newly obtained GQDs exhibited low cytotoxicity with an advantage of strong photoluminescence in the cells, and thus the GQDs might be used as a bioimaging marker in tumor cell imaging.

Key words: graphene quantum dots, electrochemistry, fluorescence, tumor cell, bioimaging