Development of colorimetric sensing assay for cysteine detection using Arduino based read-out method

Abstract

This study presents the development of a simple, rapid, and highly selective colorimetric detection method for cysteine based on its interaction with a Chromium (III) chloride hexahydrate and diphenylcarbazone (DPC) complex. The sensing mechanism relies on the ability of cysteine to reduce the Cr-DPC complex, leading to a distinct color change from purple to green. This reaction completes within 30 minutes and is easily visible to the naked eye, allowing preliminary detection without sophisticated instrumentation. Cysteine detection is clinically significant due to its relation to cystinuria, a rare inherited disorder characterized by defective renal reabsorption of cystine and other dibasic amino acids. Excess cystine in the urine leads to the formation of cystine stones, causing recurrent kidney stone episodes, pain, and potential kidney damage.