Abstract
This paper is aimed at reviewing the application of biological extracts from plants, fungi and bacteria in the synthesis of metal/metal oxide nanoparticles with reference to Ag and TiO2 nanoparticles as a case study. The procedures for the extraction of the biological extracts as well as the chemical instrumentation analysis of the extracts and metal/metal oxide nanoparticles were explained in this review. It was reported that standard chemical test confirms the presence of tannins, alkanoids, flavonoids and terpenoids in various plant extracts, while FTIR characterization of various biological extracts confirms the presence of organic compounds as a capping and reducing agents in the biosynthetic process for the preparation of the nanoparticles. The use of other instrumental techniques such as FESEM, XRD, SEM, EDX, TEM and UV-Visible spectroscopy in the characterization of biosynthesized metal/metal oxide nanoparticles were also explained in this review.