High biocompatible nitrogen and sulfur Co-doped carbon dots for Hg(II) detection and their long-term biological stability in living cells

• Published in: Analytica chimica acta Vol. 1245; p. 340847
• Main Authors: Khan, Waheed Ullah, Qin, Liying, Chen, Lixin, Khan, Wasim Ullah, Zeb, Shah, Khan, Asaf, Li, Shengzhen, Khan, Salim Ullah, Kamal, Sajid, Zhou, Ping
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 08.03.2023
• Subjects: Biological stability; Carbon - chemistry; Carbon - toxicity; Fluorescent carbon dots; Fluorescent Dyes - chemistry; Fluorescent Dyes - toxicity; Hg2+ detection; High biocompatible; Mercury - toxicity; Nitrogen - chemistry; Quantum Dots - chemistry; Quantum Dots - toxicity; Sulfur - chemistry; Vitro/vivo-imaging; High biocompatible; Biological stability; Fluorescent carbon dots; Vitro/vivo-imaging; Hg2+ detection; Hg(2+) detection
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2023.340847

Fluorescent carbon dots have been highly reported nanomaterials in recent times because of their excellent physio-chemical properties and various field of applications. Herein, a one-step hydrothermal approach was used to synthesize high biocompatible nitrogen and sulfur co-doped carbon dots, and examined their chemical sensing (Hg2+) and biological imaging properties. The N,S-CDs exhibited blue light, demonstrating a high quantum yield of up to 44.5% and excitation-independent fluorescent characteristics. Cytotoxicity was observed by CCK-8 assay using T-ca cells as a target source. Cell viability was recorded over 80% even after 7 days of treatment with a concentration up to 400 μg/mL, indicating low-toxicity of N,S-CDs. Notably, the bright blue fluorescence of N,S-CDs was quenched by introducing toxic Hg2+ ions into the solution. The detection limit was calculated to be about ∼3.5 nM, which is quite impressive compared to previous reports. Because of their low-toxicity, nano-size, and environment friendly properties, N,S-CDs could be excellent fluorescent agents for bio-imaging applications. The biological stability of fluorescent N,S-CDs was tested over time, and the findings were significant even after 8 days of incubation with T-ca cells. Because of good biocompatibility and bright fluorescence, N,S-CDs were suitable for in vivo imaging. [Display omitted] •N,S co-doped blue fluorescent CDs are synthesized with a quantum yield of 44.5%.•N,S-CDs show high sensitivity and selectivity towards Hg2+ with LOD 3.5 nM.•Obtained N,S-CDs have low toxicity and high biocompatibility.•The synthesized N,S-CDs are successfully uptake by T-ca cells and have long-term bio-stability.•High biocompatibility confirms the utilization of this N,S-CDs in vivo imaging.