Exceedingly biocompatible and thin-layered reduced graphene oxide nanosheets using an eco-friendly mushroom extract strategy

Abstract

Kasturi Muthoosamy,1 Renu Geetha Bai,1 Ibrahim Babangida Abubakar,2 Surya Mudavasseril Sudheer,1 Hong Ngee Lim,3 Hwei-San Loh,2,4 Nay Ming Huang,5 Chin Hua Chia,6 Sivakumar Manickam1 1Manufacturing and Industrial Processes Research Division, Faculty of Engineering, 2School of Biosciences, Faculty of Science, University of Nottingham Malaysia Campus, Semenyih, Selangor, Malaysia; 3Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia; 4Biotechnology Research Centre, University of Nottingham Malaysia Campus, Semenyih, Selangor, Malaysia; 5Low Dimension Materials Research Centre, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia; 6School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia Purpose: A simple, one-pot strategy was used to synthesize reduced graphene oxide (RGO) nanosheets by utilizing an easily available over-the-counter medicinal and edible mushroom, Ganoderma lucidum. Methods: The mushroom was boiled in hot water to liberate the polysaccharides, the extract of which was then used directly for the reduction of graphene oxide. The abundance of polysaccharides present in the mushroom serves as a good reducing agent. The proposed strategy evades the use of harmful and expensive chemicals and avoids the typical tedious reaction methods. Results: More importantly, the mushroom extract can be easily separated from the product without generating any residual byproducts and can be reused at least three times with good conversion efficiency (75%). It was readily dispersible in water without the need of ultrasonication or any surfactants; whereas 5 minutes of ultrasonication with various solvents produced RGO which was stable for the tested period of 1 year. Based on electrochemical measurements, the followed method did not jeopardize RGO’s electrical conductivity. Moreover, the obtained RGO was highly biocompatible to not only colon (HT-29) and brain (U87MG) cancer cells, but was also viable towards normal cells (MRC-5). Conclusion: Besides being eco-friendly, this mushroom based approach is easily scalable and demonstrates remarkable RGO stability and biocompatibility, even without any form of functionalization. Keywords: extraction, Ganoderma, RGO, ultrasound