In terms of synthesis there are two major routes, which include classical synthesis and green synthesis. The classical synthetic routes are well defined in the literature. However, newer environmentally conscious synthetic routes are being developed every day. The green synthesis techniques generally utilize relatively non-toxic chemicals to synthesize nanomaterials, and include the use of non-toxic solvents (such as water), biological extracts, biological systems, and microwave assisted synthesis.

Biologic synthesis of nanoparticles using plant extracts is at present under exploitation by researcher workers. The utilisation of Azadirachta indica (Neem), Medicago sativa (Alfalfa), Aloe vera, Emblica officinalis (amla, Indian Gooseberry) and microorganisms for the production of nanoparticles has been reported in the literature. The polyol components and the water-soluble heterocyclic components are largely accountable for the reduction of Ag ions and the stabilization of the nanoparticles. There are also reports on reductases and polysaccharides as factors involved in biosynthesis and stabilization of the nanoparticles.

Nanoparticle synthesis depends on the plant source, the organic compounds in the crude leaf extract, the concentration of Ag nitrate, the temperature and even the pigments in the leaf extract. The plants Basella alba (Basellaceae), Helianthus annus, (Asteraceae), Oryza sativa, Saccharum officinarum, Aloe vera leaf extract, sunflower leaf extract, Sorghum bicolour and Zea mays (Poaceae) reduce Ag ions and form Ag nanoparticles.

By altering the pH, strength of elements, plant sources and incubation temperature of the nanoparticle synthesis reaction mixture, the synthesis methods, it is possible to create a wide range of different nanoparticles. Nanoparticles of various sizes and properties may be obtained by further tapping the plant bioresources of diverse type in wild environment.