High-sensitivity colorimetric sensor based on oxidase-like Mn3O4 nanozyme for Cys detection

• Flower-like Mn 3 O 4 nanozymes show excellent oxidase activity. • Mn 3 O 4 nanozymes maintain high activity even at 5 °C. • Optimal TMB concentration enhances the detection sensitivity of colorimetric sensor. • This high-sensitivity sensor detects Cys with a limit of 0.02636 μM. Cysteine (Cys) is essential for numerous physiological processes and play a vital role in disease diagnostics, underscoring the necessity for effective and sensitive detection techniques for Cys. In this research, we introduce an ultrasensitive colorimetric approach based on oxidase-like Mn 3 O 4 nanozymes. The nanozymes were synthesized through a straightforward wet chemical method and displayed a flower-like globular morphology, showing remarkable oxidase-like catalytic performance with a low K m value of 0.1896 mM and a high V max of 2.8 × 10⁻⁷ M s⁻¹. By leveraging the outstanding catalytic activities of Mn 3 O 4 nanozymes and optimizing the TMB concentration, we developed a novel and sensitive colorimetric sensor for Cys detection. Experimental results indicated a detection range for Cys between 0.5 and 45 μM, with a lower limit of detection (LOD) of 0.02636 μM. This established method for detecting Cys reveals significant promise for the advancement of effective sensing systems.