V. Kumar, S. Mohan, D.K. Singh, R.K. Gundampati, S.H. Hasan
Indian Institute of Technology, Banaras Hindu University, U.P., India.,
Keywords: coton bonplandianum, AEC, AuNPs, TEM, Peroxidase like activity
Summary:An ecofriendly and zero cost approach have been developed for the photoinduced synthesis of more stable AuNPs using aqueous extract of Croton bonplandianum (AEC) as a reducing and stabilizing agent. The reaction mixture of AEM and HAuCl3.xH2O when exposed to sunlight turned purple which primarily confirmed the biosynthesis of AuNPs. The biosynthesis was monitored by UV–vis spectroscopy which exhibited a sharp SPR band at 530 nm after 8 minute of sunlight exposure. The optimum conditions for biosynthesis of AuNPs were 40 minute of sunlight exposure, 4.0% (v/v) of AEM inoculum dose and 1.6 mM HAuCl3.xH2O concentration. Thus obtained AuNPs was characterized through FE-SEM, HR-TEM, XRD, FTIR, AFM, and XPS analysis. The AuNPs showed gradually enhanced intrinsic peroxidase like catalytic activity and can catalyzed the oxidation of 3,3′,5,5′ tetramethyl benzidine (TMB) by H2O2 to produce a highly sensitive blue color and peak centered at 652 nm. However, the addition of glutathione caused the reduction of TMB.