Nitrogen/sulfur-co-doped carbon quantum dots: a biocompatible material for the selective detection of picric acid in aqueous solution and living cells

• Published in: Analytical and bioanalytical chemistry Vol. 412; no. 15; pp. 3753 - 3763
• Main Authors: Chandra, Subhash, Bano, Daraksha, Pradhan, Priyadarshika, Singh, Vikas Kumar, Yadav, Pradeep Kumar, Sinha, Devanjan, Hasan, Syed Hadi
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2020; Springer; Springer Nature B.V
• Subjects: Analytical Chemistry; Aqueous solutions; Biochemistry; Biocompatibility; Biocompatible Materials - chemistry; Biomedical materials; Carbon; Carbon - chemistry; Cervical cancer; Cervix; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Citric acid; Complex formation; Cytotoxicity; Electron transfer; Environmental monitoring; Fluorescence; Fluorescence resonance energy transfer; Fluorescent Dyes - chemistry; Food Science; HeLa Cells; Humans; Laboratory Medicine; Mathematical analysis; Monitoring/Environmental Analysis; Nitrogen; Nitrogen - chemistry; Phenols; Picrates - analysis; Picric acid; Quantum dots; Quantum Dots - chemistry; Research Paper; Spectrometry, Fluorescence - methods; Sulfur; Toxicity; Ultraviolet radiation; Water - analysis; Canada; India; PA; Cytotoxicity; Feasibility; Synthesis; NS-CQDs; Fluorescent probe
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-020-02629-1

Here, a fast and eco-friendly one-pot hydrothermal technique is utilized for the synthesis of nitrogen/sulfur-co-doped fluorescent carbon quantum dots (NS-CQDs) from a simple precursor of citric acid (CA) and thiosemicarbazide (TSC). The obtained NS-CQDs exhibited strong blue emission under UV light, with fluorescence quantum yield (QY) of ~37.8%. The Commission internationale de l’eclairage (CIE) coordinates originated at (0.15, 0.07), which confirmed the blue fluorescence of the synthesized NS-CQDs. Interestingly, the prepared NS-CQDs were successfully used as a selective nanoprobe for the monitoring of environmentally hazardous explosive picric acid (PA) in different nitro- and non-nitro-aromatic derivatives of PA. The mechanism of the NS-CQDs was also explored, and was posited to occur via the fluorescence resonance electron transfer (FRET) process and non-fluorescent complex formation. Importantly, this system possesses excellent biocompatibility and low cytotoxicity in HeLa cervical cancer cells; hence, it can potentially be used for PA detection in analytical, environmental, and pathological applications. Furthermore, the practical applicability of the proposed sensing system to pond water demonstrated the feasibility of our system along with good recovery. Graphical abstract