Development of plasmonic nanostructures using bottom-up approach for sensing applications

Abstract

Biosensors offer a quick and affordable option for characterizing and analyzing the presence of an analyte of interest if we compare them with a standard analytical method like spectrometry, chromatography, and microbiological technique. Biosensors have been influential in fundamental research and applications for sports, medical diagnosis, environmental conditions monitoring, and forensics. Different sensors like Enzyme-linked immunosorbent assay (ELISA), Surface plasmon resonance (SPR), and electro-chemical sensors are available at hospitals, laboratories, and test centers. However, they require professional training and are laborious to operate. In this thesis, I reported synthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) of varying sizes and shapes using a wet chemical approach. These nanoparticles have extraordinary optical, electronic, and mechanical properties depending on their size, shape, and aspect ratio. Also, they have applications like anti-bacterial, anti-tumor, water treatment, drug delivery, bio-detection, labelling, and human health care. The size, shape, inter-particle spacing, and surrounding media are some of the many factors that affect the frequency and intensity of the SPR of AgNPs. One can track Molecular interactions (bindings) on or near a particle's surface using the resonance frequency and strength of the electromagnetic (em) field. Furthermore, after that, we used them for making Localized surface plasmon resonance (LSPR) based biosensors, and for greater sensitivity, I have used them in Surface enhanced Raman spectroscopy (SERS) for the detection of Influenza A, Influenza B, Influenza A/H3 and several types of Rhino/Entero viruses.