A colorimetric sensor array based on merging silver nanozymes and gold nanoparticles for chronic kidney disease diagnosis and post-transplant monitoring.

Herein, a low cost and non-invasive approach is introduced for identifying individuals with chronic kidney disease through the design and fabrication of a colorimetric sensor array. The proposed platform integrates silver nanozymes with gold nanoparticles as sensing elements. The nanozymes, synthesized via both green and conventional chemical routes, catalyze serum metabolites and convert them into species detectable by gold nanoparticles. A total of 120 serum samples were collected from equal numbers of patients with chronic kidney disease and healthy individuals. Upon exposure of the sensor array to serum metabolites, the resulting colorimetric responses were captured using a smartphone equipped with a dedicated sensor array analysis application capable of performing visual exploratory analysis such as principal component analysis-discriminate analysis (PCA-DA). Complete discrimination between patient and healthy samples was achieved with an overall accuracy of 100%. Furthermore, the sensor correctly identified successful kidney transplantation in 87% of patients. The sensor array proved capable of monitoring treatment progression throughout the one-week to one-year post-transplantation follow-up, characterized by response shifts toward either healthy or diseased clusters. Owing to the limitations of conventional follow-up methods, including high cost and poor user friendliness, the proposed strategy offers a promising and practical alternative for chronic kidney disease diagnosis and post-transplant monitoring.