3.2 AgNPs characterizationThe biosy

3.2 AgNPs characterizationThe biosynthesis of AgNPs using Cinnamon zeylanicum barkextracts in different solvents was visually observed by thechange in color of the colloidal solutions against reductiontime. Each solvent showed different bioreduction behaviorswith respect to the reduction time. In aqueous extract, thecolor changed from yellow to dark brown within 15 min ofreduction time indicating the immediate formation of AgNPs.Whereas in ethanol extract, the reduction process was relative￾ly slow, the hazy color colloidal solution changed to paleyellow after 1 h of reduction time (Fig. 4a, b). The pale￾yellow color may indicate the formation of a smaller size ofnanoparticles in the size range of 2–10 nm. In DMSO extract,the color change to light yellow and then to intense orang after 3 h of reduction time (Fig. 4c) The visual inspection ofbioreduction of silver ions is very similar to previous reportsrelated to the biosynthesis using plant extracts [34, 35]. Thecolor variation of the colloidal solution may indicate thegrowth of different morphologies of the nanoparticles indifferent solvent medium. The variation in the reduction timefor the growth of nanoparticles in different solvents is directlyrelated to the presence of biomolecules in each extract. Asseen in Fig. 4, the reduction was faster in aqueous extract incomparison to other solvent extracts. The reduction process