Layer-by-layer nanoscale-coating of microparticles with a droplet microfluidic device

This paper reports a method for the Layer-by-Layer (LbL) nanoscale coating of microparticles using a droplet microfluidic device for the first time. This so-called droplet-LbL PDMS microfluidic device consists of a droplet generator and a mixing channel. The nanoscale coating of PDDA layer on the charged microparticles called polymethacrylate has been successfully demonstrated, resulting in the change of their surface potential from -46.51 mV to 44.78 mV. The successful coating is also confirmed by the fluorescence image of microparticles coated with FITC-labeled protamine sulphate. Multiple-layers coating can be achieved by cascading the droplet generators and mixing channel with properly designed integrated rinsing components, which is under development.