Integrating recognition peptide into a nanozyme to mimic uricase binding pocket as a multifunctional nanoplatform for highly selective uric acid recognition, sensing and degrading

Nanozyme based colorimetric sensor for physiological biomarkers detection is becoming an increasingly influential technology in diagnosis, but the selective discrimination of biomarkers using single nanozyme without natural enzyme is greatly challenging. Here, a colorimetric detection platform for biomarker is successfully constructed by integrating recognition peptide (RGPT) into a nanozyme to mimic the binding pocket in natural enzyme. Firstly, RGPT-ultrafine palladium nanoparticles (PdNPs)@reduced graphene oxide (rGO) composite was facilely prepared using an arginine-rich RGPT. RGPT-PdNP@rGO composite displays outstanding laccase-like activity with K_m being 0.075 mM at significantly low dosage used, which is one magnitude lower than that of natural enzyme. RGPT-PdNP@rGO nanozyme based one-step sensor can selectively detect uric acid (UA) with a comprehensive linear range from 0.2 to 110 μM and a limit of detection of 120 nM. Moreover, RGPT-PdNP@rGO composite displays an outstanding activity for UA oxidation with K_m being 0.024 mM, revealing the nanozyme exhibits a similar affinity towards UA as natural uricase due to the cooperation of the three components. Compared with our previous work, these extremely improved UA recognition, sensing and degrading performances not only support the role of RGPT in enhancing with the recognition ability of the composite nanozyme for targeted UA, but also reveal the recognition role of RGPT is associated closely with inorganic components in the composite. This work provides more definitive and comprehensive information about multifunctional nanozymes for precise biomarker recognition by introducing recognition peptide, which is highly significant for applications beyond mimic-enzyme catalyst, including theranostic, sensing, and energy fields.