Real-time single-molecule monitoring and control of nanoparticle formation

Methods capable of controlling synthesis at the level of an individual nanoparticle are a key step towards improved reproducibility and scalability in engineering complex nanomaterials. To address this, we combine spatially-patterned activation of the photoreductant sodium pyruvate with interferometric scattering microscopy to achieve fast, label-free monitoring and control of hundreds of gold nanoparticles in real-time. Individual particle growth kinetics are well-described by two-step nucleation autocatalysis model, but with a distribution of individual rate constants that changes with reaction conditions.