Self-template sacrifice and in situ oxidation of a constructed hollow MnO2 nanozymes for smartphone-assisted colorimetric detection of liver function biomarkers

Liver function tests play a vital role in accurately diagnosing liver diseases, monitoring treatment outcomes, and assessing liver damage severity. Here, we introduce a novel approach to develop a smartphone-assisted portable colorimetric sensor for rapid detection of three liver function biomarkers: aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). This sensor is based on the inherent enzyme like activities of hollow MnO2 (H-MnO2). The H-MnO2 is synthesized via a self-template sacrifice and in situ oxidation strategy, utilizing a manganese-based Prussian blue analogue (Mn-PBA) as a sacrificial template. The resulting H-MnO2 exhibits a polycrystalline structure with a large specific surface area. By encapsulating the H-MnO2 in sodium alginate, we construct a portable sensing platform facilitating specific and rapid colorimetric detection of the three liver function biomarkers with the assistance of a smartphone. The developed sensor demonstrates outstanding sensitivity and stability, achieving detection limits of 4.9 U L-1, 3.6 U L-1, and 0.99 U L-1 for AST, ALT, and ALP, respectively. Importantly, this work introduces an innovative in situ oxidation method for fabricating hollow nanozymes, offering a cost-effective and convenient assay for liver function biomarkers detection.