Sustainable synthesis of single crystalline sulphur-doped graphene quantum dots for bioimaging and beyond. Issue 18 (11th July 2018)

• Record Type: Journal Article
• Authors: Sangam, Sujata; Gupta, Apoorv; Shakeel, Adeeba; Bhattacharya, Rohan; Sharma, Arun Kumar; Suhag, Deepa; Chakrabarti, Sandip; Garg, Sandeep Kumar; Chattopadhyay, Sourav; Basu, Biswarup; Kumar, Vinod; Rajput, Satyendra Kumar; Dutta, Malay Kishore; Mukherjee, Monalisa
• Is Part Of: Green chemistry. Volume 20:Issue 18(2018)
• Page Start: 4245
• Page End: 4259
• Publication Date: 2018-07-11
• Subjects: Environmental chemistry -- Industrial applications -- Periodicals; Environmental management -- Periodicals; 660
• DOI: 10.1039/c8gc01638k
• Languages: English
• ISSNs: 1463-9262

Abstract

Abstract : Waste-driven single crystalline sulphur-doped GQDs are synthesized via a green hydrothermal route with the highest quantum yield and excellent biocompatibility for bioimaging. Abstract : The ongoing race of biomedical applications has given momentum to the development of graphene quantum dots (GQDs). GQDs are zero-dimensional fluorescent carbon-nanomaterials, with a pronounced quantum confinement effect, and abundant edge states and functional groups. Despite their potential applications, mass-scale synthesis of single crystalline graphene quantum dots (GQDs) with high quantum yields derived via a direct green synthesis approach from bio-wastes is a major challenge. Hitherto, green extract ( i.e. sugarcane molasses) driven single crystalline sulphur-doped GQDs (S-GQDs) with a longer decay time, high quantum yield, and excellent biocompatibility have remained unexplored in the bioimaging arena. At the same time, this agro-industrial waste has value in terms of both products and byproducts i.e. zero waste generation resulting in reduced human footprint on the environment. For the first time, we present a facile, large-scale, one-step, economical, template- and catalyst-free synthesis of sustainable, highly crystalline S-GQDs via a hydrothermal route from second generation (2G) bio-wastes. Mechanistic insight into the formation of S-GQDs from their precursor was obtained using powder X-ray diffraction patterns (PXRD). S-GQDs directly obtained from bio-wastes without surface passivation showed the highest quantum yield (QY) ∼ 47% obtained to date. The wide and symmetric emission spectrum of these S-GQDs is instrumental for sensitive detection as labelling nanoprobes. Moreover, their non-toxic behavior, in vitro and in vivo, has a future in quick point-of-care screening and real-time bioimaging. Thus, the as-synthesized bio-waste derived S-GQDs accomplished the purpose of an advanced environmentally friendly and sustainable material which is non-toxic, viable, safe, and cheap. This unprecedented work advances the synthesis of high-quality S-GQDs from bio-waste, which provides a breakthrough in the bioimaging field.