Mechanism Of Drug Releasing Unit Via Oscillating Bubbles And Integration With 3-D Microswimmer

This paper presents a micro drug releasing unit of which release profile can be precisely and consistently controlled via oscillating bubbles excited by a wireless external acoustic input. The concept of the unit was reported previously, but its mechanism was not clearly understood yet. This paper experimentally shows that mass transfer occurs controllably when the acoustic bubble oscillates in a surface wave mode and the grooves on the inner tube wall are wet. The axial grooves are more critical structures for efficient mass transfer than the circumferential grooves. Based on these results, an optimal design is presented and tested showing consistent drug delivery. Then, the drug release unit is tested with immiscible liquids and real sample drug (Nyquil®), both are confirmed to be compatible with the present release unit. A large reservoir of volume 10 μL is designed for the unit and tested also showing consistent drug releases over 1 hour period. Lastly, the drug releasing unit is integrated with a micro swimming robot to demonstrate carrying and releasing of drug.