Smartphone-assisted colorimetric sensing platform based on Fe-LCDs nanozymes for detection of creatine in meat.

Creatine (CR) is an active compound closely associated with meat quality. However, current techniques for measuring CR in meat face challenges in achieving rapid and low-cost detection. In this study, nanozyme based on iron-doped carbon dots (Fe-LCDs) was synthesized by employing sodium lignosulfonate and iron as the precursors. Iron incorporation was crucial for significantly enhancing the peroxidase-like activity of Fe-LCDs. A cascade sensing platform was developed by integrating creatinase (CRH) and sarcosine oxidase (SOx) with Fe-LCDs. In this system, CR interacts with the catalytic framework to generate superoxide anions, which catalyzes the oxidation of 3,3',5,5'-Tetramethylbenzidine (TMB) to produce a blue-colored product, enabling colorimetric detection of CR. Furthermore, a sensing platform compatible with smartphones was established, successfully facilitating rapid, sensitive, and visual detection of CR in meat. This research not only synthesized an effective CDs-based nanozyme but also devised a novel and promising nanoparticle-based sensing platform for CR detection.