Compact, Seamless Integration of Active Dosing and Actuation with Microneedles for Transdermal Drug Delivery

This paper presents the seamless integration of a dosing and actuation unit capable of controlled release of liquid in the microliter range at very low flow-rates (, ul/h) with painless, hollow microneedles for transdermal liquid delivery. This novel system was tested in-vivo on human and rat skin and allows the detailed study of liquid uptake in biological tissue. Experiments with infusion of radioactive marker into rat shows that the actively infused liquid was successfully delivered trough the skin layer and absorbed by the circulatory system. It was also noted that, for the given way of device attachment, the amount of liquid that can be absorbed by the skin tissue is limited to a few ul/h. The presented device represents the first step towards a transdermal patch allowing for applications where very precise amounts of liquid need to be delivered into the skin (e.g. insulin). The novelty of this work is the significant step from non-integrated modules earlier presented by our and other groups into a complete microsystem.