Smartphone-Based colorimetric protein sensor platform utilizing an ambient ring light setup for urinary protein detection

Urine dipsticks are generally used to detect pathological changes in urine due to their low cost and easy operation, having protein parameter for diagnosis of proteinuria. Despite their advantages, results provided by the urine dipsticks generally are in a broad range. Here, we present a novel, cost-effective ambient ring light-based smartphone platform to accurately estimate urinary protein concentrations in narrower range utilizing protein sensors obtained from commercially available urine dip sticks (Mission (R) and RecombigenTM). Protein sensors changed color from yellow to green with the increasing protein concentration, having a response time of 5 min. A smartphone was used to capture images. RGB profile was extracted with the help of open-source smartphoneandroid based Color Grab application and windows-based ImageJ software. RED color intensity was found to be inversely proportional to the increasing protein concentration. Limit of detection (LOD) was found to be 130 mu g/ ml and 377 mu g/ml for Mission (R) and RecombigenTM dipstick protein sensors, respectively, when using the Color Grab app. For ImageJ, the LODs were 406 mu g/ml and 228 mu g/ml for Mission (R) and RecombigenTM dipstick protein sensors, respectively. This smartphone-based estimation of protein using dip sticks can add excellent value in the currently existing screening and diagnostics sector, especially for chronic kidney diseases.