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An innovative process of integrating microneedle array with carbon nanotube (CNT) nanofilters is developed for a novel transdermal drug delivery device with nanometer-scale selectivity and control mechanism. The SU-8 microneedle array is fabricated by the double drawing lithography process. This microneedle array is capable of penetrating stratum corneum (SC) layer. Then, drug molecules can selectively pass through CNT nanofilters with the aid of pressure, or an electric field, and are effectively delivered into the tissues under the SC layer. The CNT bundles integrated within the microneedle array act as nanofilters to block particles and molecules larger than the inner diameter of the CNTs. Moreover, the CNT nanofilters can selectively control the delivered drugs when they are under various electric fields. Three kinds of biomolecules, e.g., glucose, insulin, and hemagglutininare are investigated. The results demonstrate that the proposed novel transdermal drug delivery device can effectively deliver drug molecules in a selectively control mechanism. [ABSTRACT FROM AUTHOR]

This paper presents the design and fabrication of a single-layer out-of-plane thermal actuator. The step-bridge structure design enables bending and then buckling of the actuator in the out-of-plane direction by Joule heating. Moreover, the moving direction of the actuator can be specified by the step structure. In summary, the step-bridge actuator design has the following five merits: 1) The load-deflection relation is easily tuned; 2) the bistable buckling behavior is prevented; 3) the unwanted vibration modes can be suppressed; 4) the delamination problem is prevented; and 5) the bridge structure is stiffer and more stable. The actuator and its application on a lens positioning stage have been implemented using p++ Si layer by bulk micromachining. It demonstrates that a typical actuator would move upward with an amplitude near 13 µm when driven at 54 mW. [ABSTRACT FROM AUTHOR]