The Multifarious Applications of Noble Metal Nanoclusters in Bioelectronics Bioimaging and Biosensing

Abstract

Atomically precise metal nanoclusters (MNCs), represent a class of ultrasmall (1-3 nm) sized nanomaterials with definite number of atoms, which could possess interesting electronic, optical, and chemical features compared with conventional larger sized nanoparticles. This thesis essentially summarizes a body of work done on the synthesis, characterization and bio related applications of MNCs in aqueous medium. In first part of the thesis, the brief introduction had given on the synthetic development and subsequent characterization techniques of various noble MNCs in aqueous medium. Most importantly, they have molecular-like properties that enable fascinating optical features because of quantum confinement, allowing them to use these MNCs in a variety of catalytic, magnetic, optoelectronic, and biological applications, compared to their bulk counterparts. In the second chapter, bright red colour luminescent gold (Au) NCs were developed with six different Au NCs loadings inside the protein matrix. Subsequently, the charge transport behaviour was measured and subsequent high conductive properties among all different hybrid molecular junctions were recorded that could be useful for bioelectronic applications. In third chapter, we have focused on the synthetic development of copper (Cu) NCs in aqueous medium because easily oxidizing nature of Cu made them unstable in solution. Therefore, we have introduced a facile reaction methodology where we have successfully addressed the major limitations such as low PL QY, less colloidal stability and high toxicity through simple reaction parameter optimization approach. As a result, these Cu NCs could become a potential alternative in bio imaging applications over the other optical imaging probes such as semiconductor quantum dots, organic dyes, etc. In the fourth chapter, we investigated the optical behaviour of Cu NCs within a complex biological environment in order to use them as a better diagnostic agent. For that, we have prepared three different colours emitting Cu NCs wi