RESUMEN
@#In this paper, multifunctional silver-graphene quantum dot nanoparticles coated with phospholipids (ADG-DDPC) were prepared and their properties were evaluated <italic>in vitro</italic>. Cationic phospholipids 1,2-diolefinoxy-3-trimethy-laminopropane (DOTAP) was absorbed first onto the surface of the core of silver nanoparticle (AgNPs) through the mutual attraction between the positive and negative charge. Based on the principle of phase transformation and hydrophobic interaction, dstearyl-phosphatidylglycolamine-polyethylene-glycol-cyclic-cRGD peptide (DSPE-PEG<sub>2000</sub>-cRGD) self-assembled onto the outlayer of DOTAP of AgNPs. A stable multifunctional nano-preparation was formed and its ultraviolet absorption, particle size distribution, morphology,<italic>in vitro</italic> release behavior, ability to kill cancer cells and cell uptake were studied. The maximum UV absorption of the synthesized nanometer preparation was about 400 nm. Malvern particle size meter and transmission electron microscope showed that the particle size of the nano- preparation was about 30-40 nm and its particle size distribution was uniform. The <italic>in vitro</italic> release of nano-preparation was positively correlated with the concentration of H<sub>2</sub>O<sub>2</sub>. The IC<sub>50</sub> value of AgNPs for tumor cells was (347.78 ± 0.06) ng·mL<sup>-1</sup>, and the IC<sub>50</sub> value of ADG-DDPC for tumor cells was (209.68 ± 0.09) ng·mL<sup>-1</sup>, indicating that ADG-DDPC possessed a stronger cytotoxicity than that of AgNPs. Cell uptake experiment showed that ADG-DDPC could be absorbed by tumor cells and exhibited fluoresce inside those cells. In conclusion, ADG-DDPC was successfully prepared, and <italic>in vitro</italic>characterization study pointed to that the nano-preparation exhibits a higher antitumor activity than AgNPs.
RESUMEN
Low toxic graphene quantum dot (GQD) was synthesized by pyrolyzing citric acid in alkaline solution and characterized by ultraviolet–visible (UV–vis) spectroscopy, X-ray diffraction (XRD), atomic force micro-scopy (AFM), spectrofluorimetery and dynamic light scattering (DLS) techniques. GQD was used for electrode modification and electro-oxidation of doxorubicin (DOX) at low potential. A substantial de-crease in the overvoltage ( ? 0.56 V) of the DOX oxidation reaction (compared to ordinary electrodes) was observed using GQD as coating of glassy carbon electrode (GCE). Differential pulse voltammetry was used to evaluate the analytical performance of DOX in the presence of phosphate buffer solution (pH 4.0) and good limit of detection was obtained by the proposed sensor. Such ability of GQD to promote the DOX electron-transfer reaction suggests great promise for its application as an electrochemical sensor.