Two fold increase in synthesis of gold nanoparticles assisted by proteins and phenolic compounds in Pongamia seed cake extract: response surface methodology approach

摘要

The objective of the present study was to optimise the biosynthesis of gold nanoparticles using aqueous extract ofPongamia seed cake (PSC). Proteins, amino acids and phenolic compounds present in the PSC extract are responsiblefor reducing the metal precursor salt to nanoparticles. The levels of factors for optimisation of nanoparticles synthesiswas evaluated using UV–Vis spectrophotometer by one factor at a time studies. Further factorial design was employedto study the significant effect of various parameters on the nanoparticles synthesis. The levels of two significant factorsi.e. pH and concentration of PSC extract as obtained from factorial design were optimized further for maximumnanoparticle synthesis applying central composite design. The optimized conditions were found to be pH 3.6 and PSCextract concentration of 17.07% (w/v) at which an increase (OD at 530 nm = 1.3) in nanoparticle synthesis was observedas compared to un-optimized conditions (OD at 530 nm = 0.66). The model obtained on optimization was validated andit describes the nanoparticle synthesis aptly with an error between experimental and predicted values of just 1.15% withan R2of 0.985. It can be concluded that, RSM approach was found to be an efficient technique to optimize the reactionconditions, where a twofold increase in synthesis of small sized monodispersed gold nanoparticles was seen.