Microfluidic designing of osmotic-pressure responsive microcapsules and their applications

Abstract

Microcapsules have two compartments, aqueous core and solid shell. These core-shell structure has been intensively developed to provide controlled delivery of therapeutic agents or protected sensor materials from surroundings. However, most of microcapsules fabrication method suffer from low encapsulation efficiency and shell material limitation. To overcome such limitations, we prepare monodisperse microcapsules composed of spacious aqueous core and ultra-thin poly (lactic-co-glycolic acid) (PLGA) shell using a capillary microfluidic device. Thin PLGA membrane work as semipermeable membrane which is sensitive to osmotic pressure. Hypotonic condition makes nano-sized crack on PLGA membrane. Crack is controlled by osmotic pressure difference and thickness of PLGA membrane. We simply use homeostasis of plasma osmolality as a trigger points for release encapsulants from microcapsules in sustained manner. Such release functions render the microcap-sules appealing for in-vivo growth factor (GF) delivery. And we also adjust microcapsules to SERS sensor substrates for block non-target molecules using size-selectivity of cracked PLGA membrane.