Morphology transition of Ag nanoprisms as a platform to design a dual sensor for NADH sensitive assay

Abstract

In the present study, we designed a dual colorimetric and fluorimetric probe based on Ag nanoprisms (AgNPRs) and rhodamine B (Rh B) for NADH analysis. AgNPRs/H2O2 were utilized as a colorimetric reporter (as well as fluorescence quencher) and Rh B was applied as a fluorimetric reporter. The colorimetric probe was developed based on the protecting effect of NADH on AgNPRs/H2O2 which caused a red shift in the surface plasmon resonance (SRP) peak of AgNPRs/H2O2. The observed red shift was proportional to the NADH concentration. On the other hand, the spectral overlap between excitation and emission of Rh B and absorption of AgNPRs/H2O2 in the presence and absence of NADH was different. As a result, the Rh B fluorescence emission, quenched by AgNPRs/H2O2 (due to IFE), was retrieved in the presence of NADH. These facts were employed to establish a dual colorimetric and fluorimetric probe to detect NADH at the range of 15–300 and 30–450 nM, respectively. Both - methods were successfully exploited to NADH assay in human serum samples.