Table 1.

Several types of techniques for synthesis of nanostructured materials (Sahoo et al., 2021).

Physical techniques/methods		Chemical techniques/methods		Biological techniques/methods
Pulse laser ablation	second harmonic generation Nd:YAG (neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12) type laser is mostly used	Sono-chemical method	simple, ambient operating conditions, ease in controlling the size of nanoparticles	By micro-organisms	metallic nanoparticles, oxide nanoparticles, sulfide nanoparticles, etc. can be produced using this method
	type of laser, number of pulses, pulsing time and type of solvent affect the produced nanoparticles		earlier proposed for synthesizing iron nanoparticles, but now used for various metal and metal oxides		applications are antibacterial agents, biosensors, reaction rates enhancers, etc.
Mechanical chemical synthesis	mechanical energy enables a chemical reaction to occur	Micro-emulsions	the geometry of aggregated nanoparticles is affected by the position of water oil and surfactant phases	Using plant extracts	Ag, Ag2O, TiO2, Cu, Au, and CdS nanoparticles, etc. can be produced using this method
	the nanoparticles are recovered through suitable solvent washing		surfactant aggregates can range in size from 1 to 100 nm		applications are antibacterial, catalytic, cytotoxicity, luminescence, etc.
Phase vapor deposition	particle size and their distribution depend upon rate of evaporation and pressure of gases	Electro-chemical method	electricity is the driving or controlling force
	metal compound can be formed by using reactive gases like H2, O2, and NH3		the method is simple, eco-friendly, low costs, highly flexible, etc.
High ball milling method	planetary, vibratory, rod, tumbler, etc. are often utilized in nanoparticle synthesis
	mill type, milling, speed, duration, temperature, size, and size distribution, among other factors, all have an impact on performance
Pulse wire discharge method	metal, oxide, and nitride nanoparticles are made using this method
	a high pace of production and a high level of energy efficiency