A controlled-release microchip

Abstract

Much previous work in methods of achieving complex drug-release patterns has focused on pulsatile release from polymeric materials in response to specific stimuli¹, such as electric^2,3,4,5 or magnetic⁶,⁷ fields, exposure to ultrasound^7,8, light⁹ or enzymes¹⁰, and changes in pH¹¹ or temperature^12,13,14. An alternative method for achieving pulsatile release involves using microfabrication technology to develop active devices that incorporate micrometre-scale pumps, valves and flow channels to deliver liquid solutions^{15,<a id="ref-link-abstract-17" title="Shoji, S. & Esashi, M. Microflow devices and systems. J. Micromech. Microeng. 4, 157–171 (1994)." href="/articles/16898#ref16" aria-label="Reference 16"...}