## 3 Smart Implants Development Challenges
Integrating all these into a fabrication sequence, especially integration with other devices and small electronic components to make a miniaturized system, is a significant challenge. A heterogeneous wireless communication system with further attention to low power consumption is difficult. A great challenge is developing miniaturized wireless power transfer circuits with long-term stability for biomedical applications [43]. Using an additional circuit that is needed to rectify the generated AC output voltage is challenging because the circuit reduces the total system efficiency [43]. The main challenge is their large size because of integrating several components for the desired operation and limited ability to incorporate power delivery [43]. The challenges remain in terms of material innovation, device fabrication, and circuit design architecture [44]. Although the current micro/nanoscale technologies enable the development of biomedical electronics, the performance of the end component/device is low concerning the efficiency to that of the clinical condition and the material compatibility to a respective biological environment [45]. This must be addressed more effectively and efficiently and can be overcome with precise and accurate electronic devices, conductive interconnects, and fluidic manifolds at the micro/nanoscale dimensions to enable low power and voltage operation capability enabled by advanced micro/nanofabrication techniques. Developing a single dedicated sensor for sensing and monitoring all biological functions of multiple parameters is hard and challenging. For example, the sensor that can sense breath under different atmospheric conditions or a single sensor that can sense multiple physical functionalities such as motion, pressure, heart rhythms, etc., are challenging tasks. In addition to sensing biochemical and biophysical functionalities, sensing optical and electrical functionalities from brain neurons or neural retina are complex. Multifunctional materials, including copper-phthalocyanine, carbon, graphene, etc., could be a thought of potential materials to develop lab-on-a-chip devices capable of sensing both physical and biochemical parameters in response to changes in conditions [46; 47]. Effective nanomaterials such as photoelectric cells, piezoelectric, thermoelectric, and triboelectric materials must be explored thoroughly to meet energy requirements for electroveticals [46; 47]. The device physics with multi-material implementation concerning efficiency and their challenging limitations to match the clinical demands still needs to be explored [48; 49]. The fundamental difficulties are safety, reliability, and long-term use that must be addressed to enable potential advantages. All these essential factors come under the root of biocompatibility and material functional performance enabled by functional characteristics such as mechanical, chemical, and electrical properties [48; 49]. Devices must effectively extract physiological information by implementing signal processing and machine learning algorithms. At the same time, the device should isolate human biological motions and environmental conditions or detect multiple signals. Considering all the above, developing a miniaturized, lightweight, and battery-free wireless system within an integrated medical device to meet the requirement of portable onsite health monitoring at home or office is a critical challenge. As we discussed, there are multiple challenges and requirements related to electroveticals; we hope that the advancement in the field of bioelectronics, with the help of allied areas [50; 51], will overcome those difficulties. We believe that these technologies will become feasible from concept to reality in the near future.