CePO ₄ Nanoneedles as Nanozyme Electrochemical Biosensors for Myoglobin Detection

In this study, we developed a CePO4 nanoneedle as a nanozyme-based electrochemical immunosensor for detecting myoglobin (MYO), a key biomarker for the early diagnosis of myocardial infarction. The CePO4 nanoneedles were synthesized hydrothermally and thoroughly characterized by spectroscopic, structural, and morphological techniques. Their high aspect ratio and redox-active Ce3+/Ce4+ sites enable both efficient biomolecule immobilization and intrinsic electron mediation. The stepwise electrode modification was confirmed by FTIR and SEM analyses, which verified the successful functionalization and uniform surface coverage of the working electrode. Without requiring an external redox probe, the CePO4/Myo nanozyme-based immunosensor exhibited a linear response from 100 to 400 ng mL–1, a detection limit of 100 ng mL–1, and a correlation coefficient (R2) of 0.96. The sensor maintained stable performance for up to 21 days of storage at 4 °C, and matrix analyses confirmed its reliable detection capability in simulated real samples. Overall, this work highlights the intrinsic redox functionality of CePO4 nanoneedles, which act as nanozymes, enabling electrochemical sensing without the need for conventional redox probes. Their integration into a point-of-care platform demonstrates great potential for simple, portable, and accessible diagnostic tests.