Nanoparticle biosynthesis using unicellular and subcellular supports

Modern life is becoming increasingly sophisticated because of products engineered using designs inspired by nature. Fifty years ago, the burdock plant motivated Swiss scientists to invent Velcro, which was a simple but widely applied design that is still considered the greatest biomimetic invention yet. In nanotechnology, interest in biosynthesis of nanoparticles is increasing, particularly in the use of unicellular and subcellular supports. However, the polydispersity of the resultant structure, limited opportunity for product control and commercial applications of biosynthesized nanoparticles remain as challenges. Using different approaches, studies have attempted to understand nanoparticle biosynthesis and control of particle size and uniformity. In the biotechnological approach, gene sequences that were identified in one organism via gene silencing and were critical for nanoparticle synthesis were introduced and expressed in a different organism or overexpressed by promoters in the same organism to enhance productivity. In contrast, physical and chemical approaches were used for the control of nanoparticle synthesis. To provide a comprehensive understanding of nanoparticle biosynthesis using unicellular and subcellular supports, this review discusses recent studies and experimental evidence in the following categories: synthesis of metal, quantum dot, magnetic and bacterial protein nanoparticles. Genetic engineering is emerging as a key tool for improving the production of high-quality inorganic nanoparticles from microorganisms. Chen-Sheng Yeh and colleagues from National Cheng Kung University in Taiwan review recent strategies for synthesizing tiny metallic and magnetic crystals, quantum dots and protein nanostructures from cellular supports such as plasmids and viruses. While early biosynthetic efforts yielded nanoparticles with inhomogeneous shapes and sizes, techniques such as gene silencing and gene introduction have helped researchers better understand the natural mechanisms at work in cells. For example, proteins identified as participating in biosynthesis can be isolated and their functions executed controllably using microfluidic devices or cell extracts encapsulated by polymers. Nanoparticle applications ranging from drug delivery to molecular-scale robotics should benefit from the biocompatibility and precision offered by biosynthetic platforms. Formation of nanoparticles have shown significant improvement in quality of size, shape and dispersity based on recent advanced biosynthesis approaches by understanding the natural mechanisms underlying nanoparticles synthesis. Considering the biocompatibility, cost effectiveness and eco-friendliness, bio-associated synthesis of nanoparticles may provide the promising solutions to the challenge faced in the applications of industry and biomedicine.