Glutathione-Protected Hierarchical Colorimetric Response of Gold Nanoparticles: a Simple Assay for Creatinine Rapid Detection by Resonance Light Scattering Technique

Although numerous methods have been reported for the analysis of creatinine in human serum, the development of a simple, rapid, and practical sensor still remains a great challenge. In this work, a hierarchical colorimetric sensor was demonstrated based on the anti-aggregation effect of glutathione (GSH)-protected gold nanoparticles (AuNPs). Creatinine molecule could induce the aggregation of AuNPs, and the system could show blue color simultaneously. When GSH was added to incubate with AuNPs in advance, the solution could perform a hierarchical color change corresponding to different concentration of creatinine. Consequently, the change of AuNPs in size resulted in the difference of resonance light scattering (RLS) intensity and the quantitative detection of creatinine could be achieved. Meanwhile, the determination of creatinine in human serum could be attained with a detection limit of 1.21 μM, and the colorimetric sensor could be applied to detect creatinine in human serum successfully in a wide range from 10 to 1000 μM. As above, the creatinine in human serum could be distinguished using proper concentration of GSH. More practically, we could identify if the sample exceeded or below the critical value with our naked eye. This sensing proposal was accompanied with prominent simplicity, speediness, and practicability clinically.