Real-Time Monitoring and Control of Nanoparticle Formation

Methods capable of controlling synthesis at the levelof an individualnanoparticle are a key step toward improved reproducibility and scalabilityin engineering complex nanomaterials. To address this, we combinethe spatially patterned activation of the photoreductant sodium pyruvatewith interferometric scattering microscopy to achieve fast, label-freemonitoring and control of hundreds of gold nanoparticles in real time.Individual particle growth kinetics are well-described by a two-stepnucleation-autocatalysis model but with a distribution of individualrate constants that change with reaction conditions.