Abstract Smart devices that can monitor a patient’s health with little or no intervention from clinical staff have begun to emerge over recent years and have arisen from advances in sensing and communication technologies. The integration of vital signs monitoring systems within phone/watch systems, in addition to a range of discrete wearable medical appliances, are the first of a new generation of connected health systems that will have considerable impact on future preventative screening measures. At present, the core rationale is a “detect-alert” sequence informing either the patient or a central clinic. In cases where a rapid response may be required, a much more effective alternative would be the development of a truly smart system that could autonomously act on the information received from the sensing component and, where appropriate, deliver a therapeutic agent in a controlled manner. While the sensing strategies may be entering a mature phase of development, the designs required for the actuation of an electronic controlled delivery are still in their relative infancy and represent a considerable scientific challenge. The aim of this review is to provide a critical overview of the latest developments in functional materials and nanoscale device architectures that can facilitate controlled reagent delivery.