Research of reflectance photometer based on optical absorption

Gold-labeled lateral flow (LF) assay has been studied extensively due to its sensitiveness, simpleness, and rapidness. In this paper, scattering properties of nanogold particles and LF strip were analyzed. Based on the above analysis, a reflectance photometer has been developed for LF strip labeled by nanogold particles. The integration of reflection optical density was used to indicate the signal of T line and C line. A quantitative equation for cardiac troponin I (cTnI) was deduced to realize quantification of the real cTnI sample, whose correlation of coefficient (R2) was 0.989. The variation coefficient (CV) of repetitive experiments was less than 5%. The reflectance photometer was simple, sensitive, stable, and suitable for field detection.