Effect of Synthetic Routes on Physicochemical Properties and Biomedical Applications of Zinc Oxide Nanomaterials and Quaternary Ammonium Compounds

ZnO has acquired a large amount of attention due to its immense potential for fundamental studies regarding effects of morphology, dimensionality, and size dependent physical and chemical properties as well as their variety of applications. In the studies of nanomaterials, it has been observed that the size and shape of a nanomaterial depends on the nature of the stabilizer, i.e. surfactant, ligand, polymer to salt ratio, reaction temperature and time. The synthetic method applied also plays a role. The synthetic methods discussed in this review explain how the properties, morphology changes, affect the size, shape, and activity of ZnO nanomaterial. Especially, the electrochemical method has not been used so far. Its advantages are described. Recent advances in research on biomedical applications using ZnO indicate its potentiality as an anticancer, antidiabetic drug. Biocides, primarily those containing quaternary ammonium compounds, are heavily used in hospital environments, and various industries (food, water, cosmetic, etc). Quaternary ammonium compounds ultimately reach the environment via waste water and may remain there for a long time, due to their poor biodegradability. The potential implications of use in the emergence of antibiotic resistance have been paid little attention. This review also discusses the significance of quaternary ammonium compounds in biomedical applications. We have used tetra alkyl quaternary ammonium salt as capping agent and as a supporting electrolyte in the synthesis of ZnO NPs by electrochemical method. This method produces fine ZnO particles in the pure form. Combination of ZnO, quaternary ammonium compounds and use of electrochemical synthesis method may help in developing a new strategy towards sensing and drug delivery applications. The versatile use of quaternary ammonium compounds has been reported, their risk factors must be taken into account while choosing the compounds. Although ZnO NPs are proven to be a future potential, their toxicity is the main concern and more in-depth understanding should be developed. Understanding of cellular and molecular pathways and clinical trials will be required in future.