2 minute read
Elizabeth Roque
Synthesis, characterization, and photothermal effect of CuS nanoparticles deposited over graphene oxide nanosheets
Elizabeth Roque
Mentor: Gururaj Neelgund Department of Chemistry
Introduction: Cancer is one of the current major causes of morbidity and mortality of humans [1]. So, advanced therapies with high efficiency and precision are a critical need for the effective treatment of cancer. Over this passion, a promising therapy is a photothermal therapy (PTT), in which cancer cells are selectively targeted and destroyed by exposure to near-infrared (NIR) mediated high temperatures. PTT is an innovative technique in cancer therapy, and it relies on the conversion efficiency of photon energy into heat through a photosensitizer, called a photothermal agent under illumination to NIR laser. In consideration of the importance of photothermal agents in PTT, herein we designed an NIR active agent, GO-CuS, by depositing CuS nanoparticles over graphene oxide (G.O.) nanosheets. Materials and Methods: Preparation of GO-CuS: G.O. was prepared from graphite powder according to the Hummers and Offerman method with slight modifications [2,3]. In a typical procedure, 1 g of graphite powder (<20 μm, Aldrich) was added to 40 mL concentrated H2SO4 and stirred for 1 h under icecooling conditions. Then, 15 mL fuming HNO3 was slowly added and stirred the mixture for 30 min. To this, 5 g of KMnO4 was gradually added with stirring and cooling, and the resulting mixture was stirred at room temperature for 12 h followed by addition of 150 mL DI water. After stirring the mixture for 30 mins, 30 mL of H2O2 (30%) was slowly added, which turned the color of the reaction mixture to bright yellow. The resulted mixture was centrifuged and washed with 1:10 HCl in water solution in order to remove metal ions. Further, the mixture was washed with DI water until complete removal of the acids and thus obtained dark-yellow colored G.O. was dried under vacuum at 40 °C for 12 h. The drying process of G.O. was carried out at lower temperature in order to avoid its deoxygenation. Subsequently, 100 mg G.O. nanosheets was dispersed in 50 mL DI water by sonication and 20 mL aqueous solutions of CuCl2 (0.01 mol) and Na2S (0.01 mol) was added to it. The resulting mixture was allowed to stir for 4 hr at room temperature to yield GO-CuS. Results and Discussion: The prepared GO-CuS will be characterized using various instrumentation viz., IR, UV-vis-NIR, XRD, SEM, TEM, Raman, EDX and XPS. The photothermal effect of GO-CuS will be estimated by exposing its aqueous dispersion to 980 nm laser system and monitored its rise in temperature. Conclusion(s) or Summary: The robust NIR active agent, GO-CuS has been successfully prepared. The characterization of GO-CuS will be performed using different instruments and its photothermal effect will be estimated. References: [1] J.H. Lim, D.E. Kim, E.J Kim, C.D. Ahrberg, B.G. Chung, Macromol. Res. 26 (2018) 557-565; [2] W.S. Hummers, R.E. Offeman, J. Am. Chem. Soc.80 (1958) 1339; [3] G. M. Neelgund, V. N. Bliznyuk, A. Oki, Appl. Catal. B 187 (2016) 357–366.
