Novel Microgels Fabricated On Microfluidic Devices

Abstract

Microgels are micrometer sized particles consisting of a polymer network that show potential for the delivery of both hydrophilic and hydrophobic drugs. Microfluidic devices provide an excellent format for the generation of monodispersed droplets due to the precise manipulation of fluids and flow rates within the microchannels. Microfluidic droplet generation chips were therefore designed using T-junction and flow focusing geometries in glass. For microgel synthesis, monomers, crosslinker and initiator were added to the dispersed phase and water was used as the continuous phase. Controlled formation of monodisperse droplets was achieved with both geometries and droplets were collected off-chip for photopolymerisation. Three types of microgel were formed using this setup: poly(ethylene glycol) diacrylate, poly(propylene glycol) diacrylate, and tetrahydropyran acrylate - ethylene glycol dimethacrylate (THPA-EGDMA) microgels. THPA is a novel material for microgels that can be turned from hydrophobic to amphiphilic by hydrolysation. THPA-EGDMA microgels in particular demonstrated a strong response to pH changes due to the build-up of electrostatic force under high pH, showing potential for the encapsulation and release of drugs.