A novel method for the preparation of solvent-free, microwave-assisted and nitrogen-doped carbon dots as fluorescent probes for chromium(vi) detection and bioimaging

Abstract

Herein, N-doped carbon dots with excellent fluorescence characteristics were prepared by a solvent-free, microwave-assisted method and employed for the fluorometric detection of Cr(vi) and bioimaging.

Preparation of carbon dots with orange emission for Cr(Ш) detection and cellular imaging

“…In order to evaluate the biological applications of OCDs for the determination of Cr(Ш) in living cells, the cytotoxicity against HeLa cells was investigated using MTT colorimetric assays. As shown in Figure 9, 92.5% cell viability was observed Cu(П) 365 0-80.0 5.3 [24] Zn(П) 440 0.14-30.0 0.14 [25] Co(П) 376 0.5-3.0 0.12 [26] Cr(VI) 350 1.0-80.0 0.86 [27] Cr(VI) 360 5.0-100.0 0.12 [28] Cr(Ш) 500 1.0-96.0 0.38 This work after incubating HeLa cells with OCDs (from 0 to 300 μg/mL) even for 36 h. So these OCDs exhibited low cytotoxicity and good biocompatibility to living cells [29], which indicated that the OCDs were novel carbon materials with excellent health friendliness.…”

Fluorescent “on–off–on” sensor based on N,S co-doped carbon dots from seaweed (Sargassum carpophyllum) for specific detection of Cr(vi) and ascorbic acid

“…It indicated that the absorption spectrum of Cr(VI) not only overlapped precisely with the excitation spectrum but also the emission spectrum of N,S-CDs, which could cause part of the emission light from CDs to be shielded by Cr(VI) because some excitation energy of the CDs was subdued. 48,49 What's more, the lifetimes of N,S-CDs and N,S-CDs/Cr(VI) were presented in Fig. 5b.…”

Heavy metal ion detection using green precursor derived carbon dots

“…A gap of 1–2 mm is maintained for steady discharge. High-energy (4000–6000K temperature) plasma is produced because of the electric current, resulting in carbon vapors drifting toward cathode ( He et al., 2016 ; Cao et al., 2019 ), leading to the formation of CQDs ( Ludmerczki et al., 2019 ).…”

“…Some CDs reported using microwave technique with green carbon precursors are lotus roots ( Gu et al., 2016 ), potato dextrose agar ( Gupta et al., 2016 ), table sugar ( Ansi and Renuka, 2018 ), quince fruit powder ( Ramezani et al., 2018 ), green natural kelp ( Zhao et al., 2019a ), and flour ( Qin et al., 2013 ). Although some CDs could be synthesized via microwave (using organic solvents), they have found limited use in biomedical applications because of certain toxicity levels, solid state synthesis in microwave of CDs has been demonstrated to be relatively more effective and less toxic ( He et al., 2016 ; Cao et al., 2019 ).…”