Work

Bioenzyme-free dual-mode sensing: Fe-N/C single-atom nanozyme integrated smart hydrogel for visual detection of carbosulfan

Year: 2025

Type: article

Abstract: Quick and sensitive monitoring of Carbosulfan (CBF) residues in food is of great significance to guarantee food safety. This study developed a simple, portable, and enzyme-free sodium alginate hydrogel probe (SA-Hydrogel probe) for the colorimetric and fluorescent rapid detection of CBF. Iron single-atom nanozyme (Fe-N/C SANs) with excellent oxidase-like activity was synthesized via high-temperature pyrolysis, which catalyzed the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) into a blue product (oxTMB). Red-emissive carbon dots (R-CDs) with aggregation-induced emission property were introduced as a reference signal, and the generated oxTMB quenched the red fluorescence of R-CDs through the inner filter effect (IFE). However, acidified CBF inhibited the enzyme-like activity of Fe-N/C SANs by producing reductive sulfide ([SH]), leading to a reduction in oxTMB generation. Additionally, the weakened IFE led to the recovery of R-CDs’s fluorescence. The probe exhibited a good linear response to CBF within the range of 0.05–20 μg/mL, with calculated limits of detection (LODs) of 0.025 μg/mL and 0.012 μg/mL based on the color parameter (G+B)/2 R (colorimetric) and R (fluorescent), respectively. This study not only innovatively constructed an enzyme-free dual-mode sensing platform for the rapid identification of CBF but also provides new insights for the development of portable pesticide residue detection devices.

Source: Sensors and Actuators B Chemical

DOI: 10.1016/j.snb.2025.138677