Eco-compatible Synthesis of Metal Nanoparticles Using Bacterial Nanofactories and Their Applications in Optoelectronics and Magnetic Technologies

Nano revolution in the field of optoelectronics and magnetic technologies has directly influenced the developmental pace of advanced devices. The application of various metal nanomaterials has played a significant role in the formation of these advanced devices, their function, durability, and performance. Conventionally synthesized metal nanomaterials have major limitations such as being environmentally hazardous, costly, requiring cumbersome infrastructure, highly toxic, and less energy efficient. Therefore, there is an urgent need to overcome these issues and utilize an approach that is simple, energy efficient, non-toxic, low cost, and sustainable. A ground breaking approach known as “Green synthesis” has emerged as an inevitable method for metal nanoparticle synthesis. This approach utilizes biological entities, both intracellular and extracellular systems, to produce metal nanoparticles. Various biological entities have been explored and utilized as model systems for nanoparticle synthesis, including viruses, fungi, lichens, algae, plant extracts, and animal tissue. Among them, bacterial systems have proven to be the most preferable candidates due to their rapid growth rate, ease of cultivation, high secretion of extracellular enzymes in nature, ability to bio-accumulate metals, and capacity to survive in extreme conditions. The bacterial cell is well suited for large-scale production of metal nanoparticles which can be utilized for optoelectronic and magnetic applications. The methods employed for green synthesis using biological precursors heavily rely on numerous crucial parameters such as the choice of solvent, pH conditions, pressure and temperature. The mechanism for bacteria-mediated nanoparticle synthesis is majorly divided into two parts: extracellular mode of mechanism and intracellular mode of mechanism. The extracellular mode of synthesis involves the synthesis surface/ outside of the bacterial system. The extracellular synthesis is further divided into three parts (1) bioleaching (2) bio-sorption (3) biotransformation. The intracellular synthesis is further divided into two parts (1) bioaccumulation and (2) bio-assimilation process. This chapter provides a comprehensive overview of the synthesis of various bacteria-mediated metal nanoparticles and their applications for flexible electronic and magnetic applications. Also, the impact of the biomolecules involved in the synthesis of inter or intracellular nanoparticle synthesis, and the properties of synthesized nanoparticles. This chapter provides new insights and perspectives on the latest and novel biological materials, which can be utilized in various application areas.