Smart Responsive Microarray Patches for Transdermal Drug Delivery and Biological Monitoring

Traditional drug delivery routes possess various disadvantages which make them unsuitable for certain population groups, or indeed unsuitable for drugs with certain physicochemical properties. As a result, a variety of alternative drug delivery routes have been explored in recent decades, including transdermal drug delivery. One of the most promising novel transdermal drug delivery technologies is a microarray patch (MAP), which can bypass the outermost skin barrier and deliver drugs directly into the viable epidermis and dermis. Unlike traditional MAPs which release loaded cargo simultaneously upon insertion into the skin, stimuli responsive MAPs based on biological stimuli are able to precisely release the drug in response to the need for additional doses. Thus, smart MAPs that are only responsive to certain external stimuli are highly desirable, as they provide safer and more efficient drug delivery. In addition to drug delivery, they can also be used for biological monitoring, which further expands their applications. This review focuses on the application of smart responsive microarray patches (MAPs) in drug delivery and biological monitoring. Compared to conventional MAPs which release drugs into the skin as they penetrate it, responsive MAPs only work upon receiving biological or external stimuli, thus offering a potentially safer and more efficient drug delivery and biological monitoring solution.