Single-probe sensor array based on inorganic salts for simple, rapid, and low-cost colorimetric identification of...

The simple, rapid, and cost-effective identification of proteins holds significant importance in the clinical domain, particularly concerning disease diagnosis, inflammatory markers, and cancer biomarkers. In this study, we developed a single-probe colorimetric sensor array for protein identification, using inorganic salt solutions as sensing elements and silver nanoparticles (AgNPs) as indicators. Inorganic salts influence protein folding, leading to varied interactions between AgNPs and proteins, thereby generating distinct response patterns. This approach simplifies the preparation of sensor arrays, enhances detection efficiency, and provides a multidimensional information-rich strategy. Identification was achieved through either absorbance measurements using a microplate reader or by extracting RGB values from images captured by a smartphone. The sensor array enabled the identification of 17 different proteins and protein mixtures within 30 minutes. Furthermore, it discriminated varying concentrations of catalase and transferrin in urine with 100% accuracy. This simple, rapid, and cost-effective colorimetric approach shows promise for clinical diagnostics and proteomics applications.