Wearable ultrasound bioelectronics for healthcare monitoring

Customized and personalized healthcare, being self-administered by patients, is highly sought after in light of the increasing burdens chronic illnesses aging populations. Outside clinics that empower individuals to have a more prominent role managing their health are becoming trend due many benefits. For example, they can reduce hospital visits infection risk during pandemic like COVID-19. Flexible bioelectronics, which be mounted onto skin, attached clothing, even implanted into bodies (e.g., epidermal electronics, wearable implantable electronics) ideal candidates for this purpose.1Huang Y. Su Jiang S. Electronics: Theory Method Structural Design. Springer Nature, 2023Google Scholar Different from conventional medical instruments hospitals usually bulky, non-portable, mono-functional, time-consuming,2Jiang L. Wu J. Emerging ultrasonic bioelectronics healthcare.Prog. Mater. Sci. 2023; 136101110Crossref Scopus (1) Google flexible enable continuous, non-invasive, real-time, comfortable monitoring vital physiological signals, offering clinically related information disease diagnosis, preventive rehabilitation care. This technology holds great promise tracking conditions such as cardiovascular problems, metabolic disorders, diabetes, significance rapidly population. Moreover, ultrathin, low-modulus, lightweight, rendering them “mechanically invisible” objects with arbitrary surfaces. Fueled rapid development materials manufacturing technologies, an era flexible, wearable, conformal devices above horizon. Based on working mechanisms, nowadays classified three categories2Jiang Scholar,3Jiang Liu X. et al.Flexible metamaterial electronics.Adv. 2022; 342200070Crossref (21) Scholar: mechanical utilize own deformation realize measurements, strain or pressure sensors human motion monitoring; (2) rely light-matter interaction deliver biometric information, photonic skin non-invasive molecular sensitivity; (3) sound exploit sound-matter interaction, ultrasound imager cardiac imaging. Among these, most frequently utilized, contact approach simplest straightforward. Comparatively, advantages aspects non-invasiveness, low hysteresis, high sensitivity, insusceptibility electromagnetic interference, large capacity multiplexing. However, clinical applications limited finite wavelength-dependent light-penetration depth. The emerging potential overcome these limitations, offer power consumption, miniaturization, sufficient penetration depth, spatial resolution.2Jiang Recently, especially has garnered significant interest. Several impressive achievements infant field emerging, bioadhesive capable long-term continuous imaging diverse organs4Wang C. Chen Wang al.Bioadhesive organs.Science. 377: 517-523Crossref PubMed (67) intrinsically stretchable imaging.5Hu H. Huang Li M. al.A imager.Nature. 613: 667-675Crossref (16) They representative showcasing works so far, displaying two different developmental pathways. former consists thin rigid probe adhered via couplant made soft, tough, antidehydrating, hydrogel-elastomer hybrid. It emphasizes rather than biodevice itself. enables density element arrays (400 elements per square centimeter), resolution, multifunctionality internal organs blood vessels, muscle, heart, gastrointestinal tract, lung), stable quality dynamic body movements, robust reliability long-term, (48 hours) applications. primary challenges type remain wearing discomfort material characteristics (including electrical, optical, thermal, chemical, acoustic properties) couplants. In comparison, latter follows current making biodevices attachment body. features piezoelectric transducer arrays, liquid metal composite electrodes, triblock copolymer encapsulation. entire device Young’s modulus 921 kPa stretchability up approximately 110%, while about 1 MPa 20%, respectively. performance (as measured signal-to-noise ratio, location accuracy, range, contrast-to-noise ratio), combined capabilities echocardiography several views, motion, automatic image processing, provides heuristic paradigm imager. despite advances flexibility, still strictly lack stability reliability, means it unable provide comparable conventional, stiff, non-stretchable probes. Specifically, suffers limitations unstable motions, short duration, susceptibility external disturbance, liable failure. Achieving both functionality convenience toward practical applications, number technological research opportunities lay ahead need addressed (Figure 1). Initially, currently available studies primarily concentrate design production probes, extensive, wired, data acquisition system. Future endeavors prioritize wireless systems, integration. instance, system scaled down size mobile phone. Second, addition imaging, also extended hybrid light, photoacoustic/optoacoustic additional structural functional resolution improve probing complex environments hence expand scope Furthermore, functions based mechanisms verify each other, avoiding false positives negatives thus improving robustness Third, advanced algorithms conducive accommodating phase distortion therefore artifacts originating non-planar chest. essential deep-seated organs. Fourth, demonstrated functionalities prototypes infancy mostly laboratory research, sometimes solely demonstrations under assumptions, without considering real-life environment. Clinical-grade metrics various should taken account. Fifth, embrace almost platform AI-assisted tremendous amount provided machine learning training datasets. would exciting develop healthcare GPT-4. Sixth, micro-/nano-scale high-precision fabrication techniques prerequisite. Many early stages, liquid-based printing, laser-based techniques, lithography photo- two-photon), recent fashionable 4D printing. Last but not least, substantially relies exploration maturation materials. majority involve mechanical, photoelectric properties materials, few pay attention As interdisciplinary exhibit inherent complexity diversity. realization necessitates extensive in-depth cooperation researchers practitioners across all disciplines, including chemistry, physics, mechanics, algorithms, software, hardware, medicine, more. disciplines inevitably show divergent characteristics. already reported just tip iceberg, waiting explored. Conceptual breakthroughs, multidisciplinary demand-driven innovative key future work. If growth continues, inconceivable witness near-explosion academic industrial Such outcome was witnessed over last decade recently closer bioelectronics. appear next. work supported National High Level Hospital Clinical Research Funding (Grant No. 2023-GSP-QN-23), Natural Science Foundation China 52105575), Fundamental Funds Central Universities QTZX23063), Proof Concept Xidian University Hangzhou Institute Technology GNYZ2023YL0302). authors declare no competing interests.