Preparation of monodisperse PEG hydrogel microparticles using a microfluidic flow-focusing device

A microfluidic assisted preparation method of nearly monosized poly(ethylene glycol) (PEG) microparticles has been described. Three types of microfluidic flow-focusing devices with different geometries were fabricated using polydimethylsiloxane (PDMS). Microdroplets of PEG hydrogel were successfully prepared in the microfluidic flow-focusing devices by adjusting the flow rates of the continuous phase, namely, mineral oil, and the dispersed phase, viz., hydrogel solution. Then, the microdroplets of PEG hydrogel were cured by UV irradiation. Various experimental conditions pertaining to the geometry of the microfluidic flow-focusing device, flow rates of the dispersed and continuous phases, and concentration of PEG hydrogel solution were investigated and optimized to fabricate monosized PEG hydrogel microparticles. The prepared PEG microparticles were nearly monosized in the range of 40 μm to 200 μm in diameter according to the above experimental conditions. Then, PEG hydrogel particles laden with microbeads of 6 μm diameter were fabricated using the microfluidic flow-focusing devices with the optimized conditions.