Frequency-controlled wireless shape memory polymer microactuator for drug delivery application
This paper reports the wireless Shape-Memory-Polymer actuator operated by external radio frequency magnetic fields and its application in a drug delivery device. The actuator is driven by a frequency-sensitive wireless resonant heater which is bonded directly to the Shape-Memory-Polymer and is activated only when the field frequency is tuned to the resonant frequency of heater. The heater is fabricated using a double-sided Cu-clad Polyimide with much simpler fabrication steps compared to previously reported methods. The actuation range of 140 μm as the tip opening distance is achieved at device temperature 44 °C in 30 s using 0.05 W RF power. A repeatability test shows that the actuator’s average maximum displacement is 110 μm and standard deviation of 12 μm. An experiment is conducted to demonstrate drug release with 5 μL of an acidic solution loaded in the reservoir and the device is immersed in DI water. The actuator is successfully operated in water through wireless activation. The acidic solution is released and diffused in water with an average release rate of 0.172 μL/min.
KeywordsMEMS Microfabrication Microactuators Shape memory polymer LC circuit Wireless power transfer Drug delivery device
The authors acknowledge the financial support from Ministry of Science, Technology and Innovation Malaysia under E-science Fund (03-01-06-SF1211) and Ministry of Higher Education Malaysia (MOHE) under PRGS (1/13/TK04/UTM/02/01) and FRGS (2/2014/TK01/UTM/02/3) schemes. M. A. Zainal acknowledges the financial support from Universiti Teknologi Malaysia (UTM) under Zamalah scheme.
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