Reduction degree and property study of graphene nanosheets prepared with different reducing agents and their applicability as a carrier of the Ru(phen)3Cl2 luminescent sensor for DNA detection

Abstract

Recently, graphene nanosheets (GNS) have been widely investigated and used in capacitors, catalysts, biological/chemical sensors, etc. However, the feasible applications of GNS prepared with different reducing agents as a carrier of luminescent sensors have never been systematically studied yet. Herein, a series of GNS were acquired using different reducing agents, such as hydrazine, glucose and urea. The reduction degrees and properties of the GNS samples were systematically studied by using an X-ray diffractometer, Raman spectra, IR spectra and X-ray photoelectron spectroscopy. The results indicated that the reduction degree was in the order of hydrazine > glucose > urea, demonstrating that reducing agents play an important role in the bulk fabrication of high quality graphene. Then the GNS samples were all employed as a carrier of the Ru(phen)₃Cl₂ (tris(1,10-phenanthroline)ruthenium(II) dichloride) sensor to discriminate DNA. It is found that all the GNS samples can effectively quench the emission of the Ru(phen)₃Cl₂ sensor. After the addition of a certain amount of DNA into the corresponding systems, the luminescence intensity was fully recovered. In comparison, the luminescence response of GNS-G prepared with glucose shows the best linear correlation to the DNA added, with a detection limit of 3.62 × 10⁻⁹ g mL⁻¹, indicating GNS-G can be employed as a good carrier of Ru(phen)₃Cl₂ to discriminate DNA. This work will significantly advance the research of bulk fabrication of high quality graphene and the specific applications in luminescent sensors of graphene-based functional materials in the future.