Cellphone-based attomolar tyrosine sensing based on Kollidon-mediated bimetallic nanorod in plasmon-coupled directional and polarized emission architecture

In the past decade, various interfacial materials have been explored for better sensor performance in nanoplasmonics. Despite gold being an ideal candidate for many plasmonic applications, its use in the field of surface plasmon-coupled emission (SPCE) platform is limited due to its inherent quenching phenomenon. Different methodologies have been reported to circumvent this limitation, albeit compromised by complex requirements. Moreover, the SPCE enhancement obtained hitherto remains inadequate and the use of biocompatible and eco-friendly sustainable methods in this direction has been rare. In this perspective, here we demonstrate a frugal and bio-friendly technique using ubiquitously available co-polymer kollidon® to obtain silver (Ag)-gold (Au) nanohybrids. The methodology involved is a simple, user-friendly and economical UV-induced one-pot green synthesis of hybrid architectures. The nanoparticles and nanohybrids obtained through this method were studied in three different nanointerfaces, namely: spacer, cavity and extended (ext.) cavity. Dequenched as well as in excess of 1000-fold enhancement in fluorescence was obtained in the ext. cavity nanointerface on account of hybrid plasmonic resonances. In addition to this, attomolar sensitivity was achieved for biologically important amino acid, tyrosine using a mobile phone-based detection technique. The methodology reported in this work provides a straightforward technique to obtain nanohybrids that can be used to dequench the otherwise quenched emission with new physicochemical insights, in addition to providing ample opportunities for development of next-gen mobile phone based hazardous analyte detection platforms using sustainable methodologies. AgAu Nanohybrids for Attomolar Tyrosine Sensing in Smartphone-based Extended Cavity Plasmon-Coupled Dequenched Nanointerface. • Sustainable bio-polymer kollidon® mediated silver-gold rapid nanohybrid synthesis. • Simple, user-friendly and economical renewable UV-light induced one-pot approach. • 1000-fold fluorescence enhancement at functional plasmon-coupled nanointerface. • Attomolar sensitivity for tyrosine using smartphone-based detection technology.