Materials and methods: GQDs nanoparticles were synthesized by pyrolysis of L-glutamic acid and its surface was coated with PEG and amine agent to create a longer half-life and more fluorescence intensity, and it was conjugated with folic acid for better binding to MCF-7 cancer cell line with folic acid receptor by thermal method. The structure of the nanocarrier was investigated using FTIR spectroscopy, fluorimetry and TEM imaging methods. Penetration of nanoparticles into cells and their fluorescence emission were investigated by confocal microscopy.

  Results: The synthesized GQDs had a uniform, relatively spherical structure and a size below 10 nm. With the addition of amine and PEG agents to GQDs nanoparticles, significant fluorescence intensity up to 1000 a.u. was observed. According to the FTIR results, folic acid was successfully conjugated on the GQDs nanocarrier after using thermal reaction. The entry and fluorescence emission of nanoparticles into MCF-7 cells was confirmed using confocal microscopy.