Abstract
Drug delivery systems such as microspheres have shown potential in releasing biologicals effectively for tissue engineering applications. Microfluidic systems are especially attractive for generating microspheres as they produce microspheres of controlled-size and in low volumes, using micro-emulsion processes. However, the flow rate dependency on the encapsulation of molecules at a microscale is poorly understood. In particular, the flow rate and pressure parameters might influence the droplet formation and drug encapsulation efficiency. We evaluated the parameters within a two-reagent flow focusing microfluidic chip under continuous formation of hydrogel particles using a flourinated oil and an ionic crosslinkable alginate hydrogel. Fluorescein isothiocyanate-dextran sulfate (FITC-dextran sulfate MW: 40 kDa) was used to evaluate the variation of the encapsulation efficiency with the flow parameters, optimizing droplets and microsphere formation. The ideal flow rates ....