ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

N, S-Co-doped carbon dots as fluorescent probes with dual functionality for detection of picric acid and antibacterial properties

Jie Wang, Huihui Ma, Yang Wang, Cuihua Hu, Fengwen Yan, Qi Wang, Xuesong Zhao, and Tonghui Yi

School of Medical Technology, Qiqihar Medical University, Qiqihar, China

E-mail: yitonghui@126.com

Received: 29 June 2025  Accepted: 17 November 2025

Abstract:

In this study, carbon dots co-doped with nitrogen and sulfur (N, S-CDs) were synthesized from polyethyleneimine and thiourea using a simple one-pot hydrothermal technique. The synthesized N, S-CDs exhibit significant luminescent emissions, achieving a fluorescence quantum yield of 60.88%. The addition of picric acid reduced the emission intensity. The quenching mechanism is attributed to the inner filter effect. The linear detection range for picric acid is 0–300 µmol/L, with a limit of detection of 28 nmol/L. The N, S elements and C = O bonds on the surface of N, S-CDs, which not only affects the detection of picric acid but may also be related to the antibacterial activity. The antibacterial activity of the N, S-CDs was explored against both E.coli ATCC25922 and S. aureus ATCC25923.At N, S-CD concentrations exceeding 750 µg/mL, the bacterial survival rate fell below 20%.This work demonstrates that N, S-CDs possess substantial value in the detection of picric acid and in the advancement of antibacterial materials.

Keywords: Carbon dots; Heteroatom doping; Fluorescent probe; Picric acid; Antibacterial materials

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04525-3

Chemical Papers 80 (3) 2467–2478 (2026)