Optimization of biosynthesis gold nanoparticles via central composite design toward monodisperse

Abstract

The gold nanoparticles were synthesized using ultrasound radiation. The optimization process was achieved using a central composite design (CCD) and response surface methodology (RSM).The effects of gold precursor (HAuCl4.3H2O), concentration of stabilizing agent (oil palmleaves extracts, (OPLE)), sonication amplitude, and sonication time were investigated on the average hydrodynamical size and polydispersity index. The hydrodynamical size and polydispersity index of the synthesized AuNPs were measured using dynamic light scattering (DLS).The relationship between the independent variables and their corresponding responses were established by the non-linear regression equation obtained from the developedmodels. Analysis of variance was used for examining the effect of individual, cross and quadratic terms of the independent variables on the responses. As a result, very lowp-value (<0.0001), non-significant lack of fit and coefficient of the determinant (Rsize2 = 0.825, RPDI2 = 0.807) demonstrate an effective correlation between the experimental results and the predicted values. The optimal conditions selected for the expected hydrodynamical size (75nm) and the minimum polydispersity index (0.284) were modified as follows: concentration of HAuCl4.3H2O = 0.03% concentration of OPLE = 2.00%, Amplitude = 59.00%, and time = 26.32 min. Under these conditions, the average hydrodynamical size and average polydispersity indexwere found to be 71.9 nmand 0.264 respectively, which tallies well with the predicted values.