Textured surfaces as a new platform for nanoparticle synthesisElectronic supplementary information (ESI) available: Videos of nanoparticle generation on ratchet tracks. See DOI: 10.1039/c8sm00091c

We present a new, surface-based microfluidic platform for the synthesis of nanoparticles. In this platform chemical reagents are carried in separate droplets, then mixed and later transported to a desired location on the surface using surface textured ratchet tracks. This brings the advantages of both synthesizing and transporting nanoparticles in situ without having cross-contamination between samples and addressing each sample independently. This platform is also capable of carrying multiple synthesis reactions concurrently. A surface based microfluidic platform that synthesizes and transports nanoparticles using local surface energy gradients is presented.