*Phyto-Metallic Nanoparticles: Biosynthesis, Mechanism,Therapeutics, and Cytotoxicity DOI: http://dx.doi.org/10.5772/intechopen.112382*


**Table 1.** *Physicochemical properties of some plant-mediated metallic nanoparticles.*

#### *Phyto-Metallic Nanoparticles: Biosynthesis, Mechanism,Therapeutics, and Cytotoxicity DOI: http://dx.doi.org/10.5772/intechopen.112382*

how the screening of *L. minor* (duckweed) plant for phenolic compound could be done through ultra-high-pressure liquid chromatography quadrupole-time-of-flight mass spectrometry (UHPLC-ESI/QTOF-MS). Once a plant is found to be nano-active, its optimum concentration for bio-reduction of the metal ion is determined using different concentrations on a pilot scale. The optimum concentration is then upscaled in the final synthesis. Two major synthesis procedures for PM-NPs have been reported. These procedures are the addition of phytochemicals to a stirring solution of a metal salt and the addition of a metal salt solution to a solution of phytochemicals on stirring. Akinfenwa et al. reported a procedure in which optimum concentration (10 mL of aqueous 5% each) of green rooibos extract, and aspalathin compound were added to a 90 mL of 1 mM heated solution of respective gold and silver precursors while stirring at 70°C. A similar procedure for zinc oxide nanoparticles where 25 mL of aqueous 1% mango seed extract was added to 75 mL of 10 mM zinc nitrate solution maintained at 30°C in an orbital shaker was described by Rajeshkumar et al. [35, 36]. Contrarily, different concentrations of the metal precursor are added to a predetermined concentration of phytochemicals. Thipe et al. explained this method in which 100 μL of 0.1 M NaAuCl4 (in deionized water) was added to an aqueous solution of 2 mg resveratrol, a phytochemical from grapefruit in 6 mL of deionized water and the reaction mixture was stirred at room temperature and allowed to stir overnight to achieve optimal capping. Also, Elbagory et al. previously reported a method, for large-scale screening of plants with microtitre-plate. Through this method, the authors determined the optimum concentration for the biosynthesis of gold nanoparticles for further scale-up [36–38]. PM-NPs can also be synthesized by mixing plant extract clear solution with a predetermined concentration of the metal solution and boiling the above mixture at desired time and temperature while mixing. The choice of synthesis procedure depends on the hands-on experience of researchers and literature reports. In all cases, visual color change from the initial solution to the final is regarded as the first evidence for synthesis.
