Colorimetric/chemiluminescent immunochromatographic test strip by using luminol-reduced gold nanoparticles as dual-response probes

Abstract

Luminol-reduced gold nanoparticles (LuReGNPs) were prepared and utilized as dual-response signal probes for the development of a colorimetric/chemiluminescent immunochromatographic test strip (ITS). LuReGNPs-labeled antibody was adopted as the signal tracer to conduct immunoassay of mouse IgG using the developed ITS device. After 6-min competitive immunoreaction, the tracer antibody was captured on the test zone, which led to accumulation of LuReGNPs. The appearance of red color resulting from LuReGNPs accumulation on the test zone was observed by naked eyes as a qualitative and semi-quantitative signal. Moreover, luminophore in the signal probes enabled sensitive quantitation after initiating the luminol-H2O2 chemiluminescent reaction. Under the optimal conditions, mouse IgG was detected within a linear range of 0.10–100 ng/mL with a detection limit of 0.033 ng/mL (S/N = 3). The results for real biological samples detection and recovery tests demonstrated the acceptable reliability of the dual-response ITS. It exhibited great potential in both rapid screening and sensitive quantitation. Due to the merits of facile manipulation, short detection time and ideal portability, the platform could be further extended to multianalyte immunoassay of biomarker proteins for point-of-care test.