Pyrazolate-based porphyrinic metal-organic frameworks as catechol oxidase mimic enzyme for fluorescent and colorimetric dual-mode detection of dopamine with high sensitivity and specificity.

[Display omitted] • A dual-signal readout sensor with good sensitivity and selectivity has been developed for dopamine detection. • The study of catechol oxidase mimicking MOF nanozymes has the potential to expand the range of biomimetic MOFs. • The type of modular used in the synthesis process of MOFs can influence the activity of the final enzyme. Enzyme-simulating nanomaterials, with obvious advantages of high activity, stability and cost-effectiveness, can surrogate the complex natural enzymes and catalyze enzyme-like reactions in various harsh applications. Herein, a novel fluorescent and colorimetric dual-readout sensing platform toward dopamine detection based on pyrazolate-based porphyrinic metal-organic frameworks (MOFs) by coordination regulation strategy to improve the performance of catechol oxidase mimic enzyme activity was constructed. Specifically, BA (benzoic acid) or PA (4-Formyl-1(H)-pyrazole) was introduced as auxiliary ligands to regulate the growth mode of pyrazolate-based porphyrinic MOF materials. H 4 TPP (5,10,15,20-Tetra(1 H -pyrazol-4-yl) porphyrin) and auxiliary ligands coordinated with Cu(II), exposing Cu sites with insufficient coordination and enhancing the interaction with oxygen-active species. Benefiting from the binuclear copper center structure and the preferential adsorption of reactants in the self-reinforced interface, a highly sensitive and selective detection method for dopamine based on Cu-TPP(PA) MOF material was proposed under the intervention of H 2 O 2. The feasibility of Cu-TPP(PA) MOF in detecting dopamine in human serum samples and as a paper-based analytical device was investigated. This achievement will expand the applications of MOFs in analytical chemistry and open up a new avenue for the design of highly active and stable nano-enzymes. [ABSTRACT FROM AUTHOR]