Work

UV-induced, nonenzymatic, H₂O₂-free colorimetric detection of Dopamine using MXene-based quasi-quantum dots

Year: 2025

Type: article

Abstract: This study presents a UV-activated, nonenzymatic, and hydrogen peroxide–independent colorimetric sensing strategy for the highly sensitive and selective detection of dopamine (DA), utilizing MXene-derived quasi-quantum dots (MQQDs) as photoactive nanozymes. The MQQDs demonstrate pronounced UV-activated oxidase-mimetic catalytic activity, facilitating the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) into its blue oxidized form (oxTMB) in the absence of H₂O₂. Upon the introduction of dopamine (DA), the absorbance intensity of oxTMB at 652 nm decreases progressively with increasing DA concentration. This attenuation is attributed to the redox interplay between DA and the photoexcited MQQDs, wherein DA acts as an electron donor, reducing oxTMB back to its colorless TMB form and thereby inhibiting the oxidation reaction. This electron-transfer-mediated inhibition mechanism enables quantitative colorimetric detection of DA with a detection limit of 65.4 nM. Spectroscopic analysis and kinetic fitting confirm the UV-triggered oxidase-mimetic behavior of MQQDs following Michaelis–Menten kinetics. The developed H₂O₂-free photoenzymatic platform offers a facile, stable, and environmentally benign route for DA quantification, with promising applicability in point-of-care diagnostics and neurochemical sensing.

Source: FlatChem

DOI: 10.1016/j.flatc.2025.100966

Authors: Rajapriya Govindaraju, Jongsung Kim

Institution: Gachon University

Language: English

Topic: Advanced Nanomaterials in Catalysis

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,140

Funders: Ministry of Education, National Research Foundation of Korea, Ministry of Science and ICT, South Korea