2D Ti3C2Tx MXene nanozymes based electrochemical MicroRNA biosensor and application to early diagnosis of sepsis-associated acute kidney injury.

MicroRNA detection-based molecular diagnostic methods offer a favorable pathway for the early diagnosis of sepsis-associated acute kidney injury (SA-AKI), which is crucial for reducing mortality and improving patient outcomes. In this work, a highly sensitive electrochemical biosensor was fabricated for the determination of serum miR-452-5p, an emerging biomarker for SA-AKI, leveraging the novel Ti3C2Tx MXene nanozymes and catalytic hairpin assembly isothermal amplification. Surprisingly, the two-dimensional Ti3C2Tx MXene nanozymes demonstrated remarkable electro-catalytic activity towards choline, wihch was attributed to the strong adsorption interaction between the oxygen atoms on the Ti3C2Tx MXene surface and the hydroxyl group of choline. Based on above-mentioned characteristic of Ti3C2Tx MXene nanozymes, a cascading catalytic amplification strategy by integrating Ti3C2Tx MXene with alkaline phosphatase using phosphorylcholine chloride as the substrate was designed, thereby achieving highly efficient electrochemical signal amplification. The electrochemical biosensing approach exhibited remarkable sensitivity for miR-452-5p detection, with a linear response over a concentration range from 0.1 fM to 10 nM and a low detection limit of 0.09 fM. Additionally, the developed electrochemical biosensor for direct serum miR-452-5p detection present a diagnostic efficiency of 96% in clinical samples analysis, highlighting its strong potential for the early detection and risk assessment of SA-AKI.