## 4 Discussion and Outlook  
In this review, we presented an overview of the recent advancements in LIG-based wearable systems for health care and HCI applications by using the selected sixteen examples. We discussed the design approaches, production techniques, features, capabilities, and real-world demonstrations of these systems. It can be seen that LIG, with its superior overall characteristics including excellent electrical and mechanical properties and low cost of production, can not only be utilized to create high-performance wearable single devices such as sensors and actuators, but also to create more sophisticated wearable systems. Furthermore, the trend in the development of LIG-based wearable systems in the two main application areas, health care and HCI, are becoming increasingly multifunctional and intelligent, with an aim toward integrating all the functions into a single all-in-one system. The trend toward multifunctional development has led to an increase in the integration degree of the LIG-based wearable system for health care and HCI, allowing for more functions to be realized. The system takes on several forms such as incorporating more sensors for varied signal monitoring or adding more actuators for increased interactivity. Additionally, the system not only integrates signal collection and transformation units such as sensors and actuators, but also integrates signal processing units and transmission units, which can realize a complete functional chain of information collection-processing-transmission-interaction. It is predicted that wearable health care systems will evolve into a \"portable doctor\" that combines daily physiological signal monitoring, analysis, disease warning, and diagnosis functions. For HCI-oriented wearable systems, they are expected to become a self-contained HCI interface, incorporating functions such as information receipt and transmission, processing, and interaction. Furthermore, the system can be self-sufficient through the integration of energy collection and storage modules that collect energy from the wearer's movements and sweat and store it for the use of the system. In addition to the aforementioned points, more and more innovative features will help LIG-based wearable systems play an important role in the fields of health care and HCI. For the more intelligent development trend, as LIG-based wearable systems for health care and HCI are facing an increasing amount of information that needs to be analyzed, intelligent algorithms are needed to realize efficient and accurate data processing. For health care applications, the system can be endowed with an intelligent diagnosis function, acting like a physician. For HCI applications, the intelligent algorithm can help the system efficiently process diverse information, providing the HCI system with a \"brain\" and turning it into a \"portable assistant\". In addition to utilizing software to bring intelligence to systems, some work is also beginning to explore hardware solutions [44; 45; 46; 47]. These solutions include the realization of devices with integrated sensing-storage-computing ability, neuromorphic devices, in-memory computing devices, etc. In situ processing, which occurs within the system, can improve information processing efficiency, reduce data loss and power consumption, and lead to the development of self-sufficient, closed loop wearable systems. Moreover, the multifunctional and intelligent development of the LIG-based wearable system for health care and HCI is not mutually exclusive. In fact, recent advancements show a trend toward developing wearable systems that are both multifunctional and intelligent [48; 49; 50]. One of the development goals for the LIG-based wearable system for health care and HCI is to create an all-in-one system that meets both the demands of the user and technological advances. The ideal LIG-based wearable system for health care and HCI can be analogous to an external \"information organ\" of the wearer.