Rational Biomimetic Construction of Lignin-based Carbon Nanozyme for Identification of Uric Acid in Human Urine

Nanozymes have made remarkable progress in the field of sensing assays by replacing native enzyme functions. However, it is still a challenge to rationally design active centers from molecular structure to enhance the catalytic performance and develop low-cost nanozymes. In this work, guided by the catalytic site of horseradish peroxidase (HRP), iron source and histidine were coupled to the main chain of aminated sodium lignosulfonate (SL) through the self-assembly biomimetic strategy to construct His-SL-Fe with peroxidase activity. The inherent functional groups and basic framework of aminated SL provide a robust environment and promote the formation of active sites. His-SL-Fe shows excellent robustness over multiple test cycles and has a strong affinity for the substrate compared to HRP. His-SL-Fe had been effectively integrated in the sensing system for catalytic detection of uric acid (UA) to achieve accurate recognition of UA in the range of 0.5–100 μM with the limit of detection as low as 0.18 μM. The recovery of human urine samples is in the range of 96.8%–106.1 % and the error is within 4 %. This work not only provides a new approach for the directed design of high-performance nanozymes, but also demonstrates promising ideas for the refined application of biomass resources.