Chapter 28 - Zinc-based nanomaterials: Biosafety, risk management, and regulatory aspects

Abstract

Zinc is a trace element required for essential life processes and it plays a vital role in several metabolic pathways. Zinc deficiency hampers the growth and development of plants, animals, and humans. Zinc nanomaterials can be produced from zinc oxide, zinc ferrite, and zinc carbonate and are considered cheap and safe. However, zinc oxide nanoparticles (ZnO NPs) stand out in terms of their advantages over others. With the reduced size of 1–100nm, these particles not only have smaller quantity requirements, but also offer more surface area for reactions and coverage. Zn nanoparticles have applications across manufacturing, cosmetics, healthcare, agriculture, and food industry sectors. Though zinc has been considered a safe metal by the USFDA, the indiscriminate or excessive use of the nanoparticles could cause cytotoxicity or genotoxicity to terrestrial and aquatic systems, including humans and animals, and ecotoxicity. Acute to subacute toxicity due to zinc uptake has been reported in crustaceans and zebrafish. Zinc nanomaterials enter into biological systems in three main ways: the dermal route, inhalation, and ingestion followed by blood circulation. The interaction of zinc with other nutrients, acids, etc. could be a deciding factor in regulating the application of ZnO NPs. Similarly, the size of the Zn nanomaterial, its physicochemical properties, dosage, and duration of exposure are relevant parameters for establishing the toxicity profile. The risk assessment system of Zn nanomaterials is developing, as evidenced by research papers published in this area. The use of nanoinformatics and computational material science approaches coupled with informed experiments could be deployed for accurate and dependable cyto-, geno-, and ecotoxicity assessment. For management of the risk, a holistic approach based on scientific facts and socioeconomic impacts needs to be developed. The current research gaps in biosafety, risk assessment, and risk management, and the way forward, are discussed in this chapter.