Using a T-junction microfluidic chip for monodisperse calcium alginate microparticles and encapsulation of nanoparticles

This article describes the simulation of flow velocity distribution and the process of formation of monodisperse calcium alginate microparticles (Ca-alg MPs) by using microfluidic T-junction geometries. Based on sheath stresses, water-in-oil (w/o) emulsions of an aqueous solution of a biopolymer (e.g. sodium alginate, Na-alg) are emulsified in an oil phase. The emulsions are collected into a bath containing calcium-ions to form the Ca-alg MPs. Experimental data show that Ca-alg MPs with diameters ranging from 70 μm to 220 μm with a variation less than 10% are precisely generated. The size of the emulsions can be tunable by adjusting the relative sheath/sample flow rate ratio. In addition, the encapsulation of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) is studied. The approach in manipulation of microparticles will provide many potential usages for pharmaceutical application. The proposed method has advantages of being readily controlled, cost-effective and easy to operate, together with its ability to produce a uniform size.