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Soft and stretchable electronics have emerged as highly promising tools for biomedical diagnosis and biological studies, as they interface intimately with the human body and other biological systems. Most stretchable electronic materials and devices, however, still have Young’s moduli orders of magnitude higher than soft bio-tissues, which limit their conformability and long-term biocompatibility. Here, we present a design strategy of soft interlayer for allowing the use of existing stretchable materials of relatively high moduli to versatilely realize stretchable devices with ultralow tissue-level moduli. We have demonstrated stretchable transistor arrays and active-matrix circuits with moduli below 10 kPa—over two orders of magnitude lower than the current state of the art. Benefiting from the increased conformability to irregular and dynamic surfaces, the ultrasoft device created with the soft interlayer design realizes electrophysiological recording on an isolated heart with high adaptability, spatial stability, and minimal influence on ventricle pressure. In vivo biocompatibility tests also demonstrate the benefit of suppressing foreign-body responses for long-term implantation. With its general applicability to diverse materials and devices, this soft-interlayer design overcomes the material-level limitation for imparting tissue-level softness to a variety of bioelectronic devices.

Silicon (Si) is broadly used in electrochemical and photoelectrochemical devices, where the capacitive and Faradaic reactions at the Si/water interfaces are critical for signal transduction or noise generation. However, probing the electrified Si/water interface at the microscopic level remains a challenging task. Here we focus on hydrogenated Si surfaces in contact with water, relevant to transient electronics and photoelectrochemical modulation of biological cells and tissues. We show that by carrying out first-principles molecular dynamics simulations of the Si(100)/water interface in the presence of an electric field we can realistically correlate the computed flat-band potential and tunneling current images at the interface with experimentally measured capacitive and Faradaic currents. Specifically, we validate our simulations in the presence of bias by performing pulsed chronoamperometry measurements on Si wafers in solution. Consistent with prior experiments, our measurements and simulations indicate the presence of voltage-dependent capacitive currents at the interface. We also find that Faradaic currents are weakly dependent on the applied bias, which we relate to surface defects present in newly prepared samples.

The ultimate goal of the advancements in bioelectronics and robotics is the creation of seamless interfaces between artificial devices and biological structures. Current efforts in this area have been focused on designing biocompatible, mechanically compliant, and minimally invasive electronic and robotic systems for a range of applications, such as motor control and sweat sensing. The purposeful design of bioelectronic and robotic systems using the principles of biomimicry enables the creation of biocompatible and life‐like machines and electronics. The success of such approaches relies on the new development and applications of soft materials, as well as methods of actuation and sensing that are inspired, either by composition, function, or properties, of the naturally occurring organisms. A combination of rigid structural components, soft actuators, and flexible sensors can enable the integration of such devices with biological organisms and eventually human users. In this review, we highlight the recent advances in biomimetic soft robotics and bioelectronics. We describe the soft robotic fabrication toolbox and modern solution in bioelectronics that, in our opinion, will enable the fusion of these fields by creating robotic bioelectronic systems. Future development in this area will require substantial integration of adaptable and responsive components at the biointerfaces.

Biocompatible and nanoscale devices for biological modulation of cells and tissues possess the potential for tremendous impact on medical and industrial technologies. Typical medical devices and therapies tend to be macroscale, comprised of nonbiocompatible materials, and broadly targeted, resulting in imprecise treatments and adverse effects such as chronic immune response and tissue damage. The development of nanoenabled and biocompatible technologies—ranging from biodegradable nanoparticles for localized drug delivery to transient electronic devices for stimulation therapy to engineered biofilms with applications to nanomedicine—will continue to enable the advent of personalized medicine and precision therapies. In this review, recent research into this frontier is reviewed, first analyzing the synthesis of nanoenabled and biocompatible technologies and then presenting significant considerations regarding the development of such materials. Lastly, the latest advancements in biocompatible, nanoenabled devices are examined, followed by a discussion of the direction of future research in the field.