Discontinuous dewetting (DD) is an attractive technique that enables the production of large liquid arrays in microwells and is applicable to the synthesis of anisotropic microparticles with complex morphologies. However, such loading of liquids into microwells presents a significant challenge, as the liquids used in this technique should exhibit low mold surface wettability. This study introduces DD in a degassed mold (DM), a simple yet powerful technique that achieves uniform loading of microparticle precursors into large microwell arrays within 1 min. Using this technique, hydrogel microparticles are produced by different polymerization mechanisms with various shapes and sizes, ranging from a few micrometers to hundreds of micrometers. Hydrophobic oil microparticles are produced by the simple plasma treatment of the DM, and agarose microparticles encapsulating bovine serum albumin (in a well-dispersed state) are produced by submerging the DM in fluorinated oil. To demonstrate additional functionality of microparticles using this technique, high concentrations of magnetic nanoparticles are loaded into microparticles for particle-based immunoassays performed in a microwell plate, and the immunoassay performance is comparable to that of ELISA.
Keywords: anisotropic microparticle; degassed mold; discontinuous dewetting; fluorinated oil; hydrogel; magnetic nanoparticle.