8.4.1.4 The fourth generation：controlled and feedb...
The fourth generation of TDD technology emerged in the context of individualized treatment and multidisciplinary intersection.It is based on a patch which is integrated with soft ultra-thin wearable intelligent device，bioelectronic devices and drugs.The patch can closely adhere to the skin to monitor the physiological signals（e.g.，blood pressure and body temperature），electrophysiological signals（e.g.，electrocardiogram and electroencephalogram）and biochemical signals（e.g.，pH values of sweat and body fluid，levels of blood glucose and blood oxygen）through biosensors.These signals are transmitted to the actuator to control the release of the corresponding drugs according to demand，forming a biosensor-actuator feedback loop.Currently，the fourth generation of TDD technology is still in the early research stage（see chapter 10 Wearable Skin Devices and Electronic Skin for details）.(https://www.daowen.com)