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Sung Hoon Kang, HEMI Fellow, assistant professor in the Department of Mechanical Engineering, and associate researcher at the Institute for NanoBioTechnology, has written a focus article about the fabrication of and potential applications for an electrically-controlled shape-memory microactuator that operates in a solution matching the ion concentration of the human body. The article was published in Science Robotics and includes contributions by Kang’s graduate students Mostafa Omar and Bohan Sun.

Titled “Good reactions for low-power shape-memory microactuators,” the article details the mechanism of the microactuator and its potential versatile applications. The microactuator has two configurations: bent and flat. When the bent microactuator is exposed to an electrochemical oxidation reaction, an oxide layer grows on its surface, expanding and flattening the device into its flat configuration. The oxide layer stays after the reaction, which allows the device to maintain its shape without applying voltage. As such, it is especially useful for robots operating with limited power supplies.

The article showcases the versatility of microactuators in extreme environments. For example, in medicine, applications can include: controlled drug delivery, temporary clamps in place of stitches, and fast-response devices against blood clots in arteries. Other applications include use as a microvalve to control flow in microfluidics and reconfigurable optical metamaterials/metaservices. Its potential for application can be further increased by improving energy efficiency, speed, actuation range, and durability.

Read the focus article here.