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Self-signaling colorimetric sensor for selective detection of dopamine based on CoFe2O4 nanozyme accelerated dopamine
Panpan Sun1, Juan Chen1, Qian Li1
1Key Laboratory of Water Security and Water Environment Protection in Plateau Intersection (NWNU), Ministry of Education, Key Lab of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, 730070, Lanzhou, Gansu, China.
Background:
Reliable and selective detection of dopamine is crucial for the early diagnosis of various diseases. Transition metal based-nanozymes have shown great promise in the field of colorimetric detection of dopamine due to their remarkable stability and exceptional catalytic efficiency. However, these transition metal-based nanozymes typically function through a chromogenic reaction that relies on additional organic substrates, such as 3,3',5,5'-tetramethylbenzidine, to generate a detectable signal. The presence of various co-existing substances can cause serious disturbances due to their possibly similar oxidation potentials.
Results:
In this study, we proposed a 3,3',5,5'-tetramethylbenzidine-free strategy based on the self-signal of dopamine to achieve reliable and selective detection. CoFe2O4 nanozymes with catalase-like activity was selected as a catalyst to accelerate the polymerization of dopamine to reduce the reaction time and harsh conditions required for its self-polymerization. As neither ascorbic acid nor uric acid can be oxidized into colored products, the 3,3',5,5'-tetramethylbenzidine-free sensor provides superior selectivity and effectiveness compared with the most 3,3',5,5'-tetramethylbenzidine-used sensor. The proposed strategy enabled quantitative detection of dopamine within a range of 5-80 μM, with a detection limit of 0.233 μM (R2 = 0.998). The limit of quantitation was 10.6 μM, and the method demonstrated a precision of 2.04 %. The recovery percentage for dopamine ranges from 97.0 % to 106 %.
Significance:
The proposed 3,3',5,5'-tetramethylbenzidine-free strategy offers a versatile approach for dopamine monitoring with high specificity and stability in bioanalytical applications. In addition, the strategy proposed by us also offers a rational framework for designing and fabricating highly selective sensors, thereby broadening the application of the nanozymes with catalase-like activity in bioanalysis.
