Point-of-Care Testing for Abnormal Amino Acid Metabolism: Visualized Colorimetric Detection of Tryptophan Based on Au@MnO2 Nanoparticles

 Point-of-Care Testing for Abnormal Amino Acid Metabolism: Visualized Colorimetric Detection of Tryptophan Based on Au@MnO2 Nanoparticles

Huang, Y.; Zhuang, X. T.; Zhang, R. Y.; Yu, Q. H.; Kuang, Z. W.; Qiu, C. B.; Luo, Z. F.; Rong, M. C*.

Journal of Analysis and Testing, 2025

https://doi.org/10.1007/s41664-025-00381-y

Abstract. In this study, a novel colorimetric detection method for tryptophan is developed using Au@MnO2 NPs based on their redox reaction. Tryptophan etches the outer MnO2 NPs shell and forms a stable protective layer outside the released Au NPs core in situ, accompanied by a noticeable color change from brown to pink. According to the absorbance ratio of 545 nm and 580 nm (A545/A580), a rapid (within 1 min), accurate, and specific detection method for tryptophan is constructed amidst other common amino acids. Coupling with a smartphone application, integrated Au@MnO2 NPs-based portable test strips can be used for the point-of-care testing (POCT) of tryptophan.