## 7 Conclusions  
Since the days of first pacemakers, implantable electronics systems have undergone a major transformation. The advent of micro-, nano- and molecular scale technologies have brought upon tremendous miniaturization of all components of the indwelling module, from sensors to actuators and  
Figure 3: _In vivo_ evaluations and example of a transient bioresorbable device for thermal therapy. (**A**) Images of an implanted and sutured transient electronics platform located in the subdermal dorsal region of a BALB/c mouse. (**B**) Implant site and histological section of tissue at the implant site, excised after 3 weeks, showing a partially resorbed region of the silk film. (**C**) Resonant responses of an implanted transient RF metamaterial structure before and after placement in a silk package, immediately after implantation and at several time intervals thereafter. (**D**) Measured and calculated \(Q\) factor for the metamaterial, where the results indicate transience dominated by the diffusion of biofluids through the silk package. (**E**) Transient wireless device for thermal therapy, consisting of two resistors (red outline) connected to a first wireless coil (70 MHz; outer coil) and a second resistor (blue outline) connected to a second, independently addressable, wireless coil (140 MHz; inner coil). The inset shows a thermal image of this device coupled with a primary coil operating at two frequencies, to drive both the inner and outer coils simultaneously. (**F**) Primary coil next to a sutured implant site for a transient thermal therapy device, with the inset showing an image of a device. (**G**) Thermal image collected while wirelessly powering the device through the skin; the results show a hot spot (5 \({}^{\circ}\)C above background) at the expected location, with a magnified view in the inset [166].  
electrodes. The very-large-scale integration enabled small yet efficient low-power implantable microsystems that can support increasingly complex processing. The advancement of battery technologies has allowed for the development of long-term implantable devices with high reliability, multiple functions and improved performance. Device powering via short range wireless links has been used to extend the life-time of the electronic system, with _in vivo_ energy generation and harvesting being an area of active research. The use of wireless communication technologies has extended from biomedical research to clinical health care, by enabling remote monitoring and control. Significant progress has been made with regard to the stability and biocompatibility of the packaging and encapsulation used to shield the indwelling electronics from the aggressive physiological environment. Additional functionalities, such as ability to retard bacterial attachment or encourage tissue growth, have been imparted onto these encapsulants. Together, these technologies have contributed significantly to the quality of life of the patient, preventing critical incidents and decreasing patient mortality.  
Given the ageing population, increased longevity and an ever increasing number of patients admitted into hospital care every year, the technologies that support individualized out-of-clinic automated monitoring and patient status-responsive treatment will continue to be an area of great interest and concentrated research effort. Further miniaturization of the sensing and stimulating devices will enable on-organ monitoring and highly-specific treatment delivery, without compromising normal functioning of surrounding organs and tissues. The advancement of closed loop systems will facilitate simultaneous stimulation and high-resolution sensing of both natural and evoked activity, with utility in intricate surgical procedures and neuromodulation. In addition to more sophisticated neuroprosthetics and artificial organs that will improve patient survival and quality of life, further developments in brain-computer interfacing will enhance our ability to investigate and alter cognitive or sensory-motor functions in humans.