Design and optimization of a Cu-MOF@graphene oxide nanozyme for point-of-care colorimetric determination of sarcosine and H 2 O 2

> 0.999) for linear responses to hydrogen peroxide (0.5-1000 µM, with a detection limit of 0.15 µM) and sarcosine (0.5-250 µM, with a detection limit of 0.16 µM). The method also demonstrated strong potential for portable analysis using smartphone-based RGB color detection, showing high precision and recovery in spiked serum samples. This work presents a computationally guided approach for designing nanozymes with enhanced catalytic activity, offering a low-cost, rapid sensor with wide linearity, high sensitivity, and unique selectivity for sarcosine detection, making it promising for portable and point-of-care prostate cancer screening applications.