Bioactivity and biomodification of Ag, ZnO, and CuO nanoparticles with relevance to plant performance in agriculture
In late 1996, the Nanotechnology Working Group was established in the US, comprised of members of various government agencies, academia, and industry to focus on advancing nanotechnology. It is estimated that the worldwide market for products with nanotechnology components will reach 1 trillion by 2015. 1 Nanoparticles (NPs), which are found in a variety of household, industrial, and medical products, have both benefits and risks related to their small size, which confers enhanced and often unique attributes compared to large-sized particles of similar chemistry. This review focuses on environmental factors that modify the biological activity, transformation, and potential relevance of silver (Ag), copper oxide (CuO), and zinc oxide (ZnO) NPs to help evaluate their risk to agriculture. We chose to study these particular NPs because they possess antimicrobial properties toward certain human pathogens, including those resistant to traditional antibiotics. However, in soil, plant growth and biogeochemical cycles rely on microbial activity that may be susceptible to intentionally or inadvertently introduced NPs. Biological activity of metal and metal oxide NPs toward microbes and plants is observed, although aggregation of the NPs occurs. The NPs act as primary sources of soluble metal so that exposed microbes and plants are faced with both particle-specific and ion-related toxicities. Bioactivity is mitigated by factors present on microbial cell surfaces, components exuded by plant roots, and materials present in soil pore water. At sub-lethal levels, the NPs change bacterial and plant metabolism to make risk prediction complex. Serendipitously, this aspect of NP interaction with bacterial cells or plants could be utilized in the production of commercially valuable metabolites. The potential for NPs to benefit plant productivity by enhancing nutrient availability and improving plant health is discussed herein. The utilization of plant and microbial metabolism for green synthesis of NPs or in remediation of NP-contaminated soils is also addressed. Maximizing these potentials demands a deeper understanding of the complex interactions and interplay between NPs, plants, and microbes relevant to the variability of different ecosystems. ¬© Copyright 2012, Mary Ann Liebert, Inc.
Dimkpa C.O., J.E. McLean, D.W. Britt, A.J. Anderson. 2012. Bioactivity and biomodification of Ag, ZnO, and CuO nanoparticles with relevance to plant performance in agriculture. Industrial Biotechnol. 8: 344-357.