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The rigidity and relatively primitive modes of operation of catheters equipped with sensing or actuation elements impede their conformal contact with soft-tissue surfaces, limit the scope of their uses, lengthen surgical times and increase the need for advanced surgical skills. Here, we report materials, device designs and fabrication approaches for integrating advanced electronic functionality with catheters for minimally invasive forms of cardiac surgery. By using multiphysics modelling, plastic heart models and Langendorff animal and human hearts, we show that soft electronic arrays in multilayer configurations on endocardial balloon catheters can establish conformal contact with curved tissue surfaces, support high-density spatiotemporal mapping of temperature, pressure and electrophysiological parameters and allow for programmable electrical stimulation, radiofrequency ablation and irreversible electroporation. Integrating multimodal and multiplexing capabilities into minimally invasive surgical instruments may improve surgical performance and patient outcomes. Soft multilayer electronic arrays on endocardial balloon catheters allow for multiplexed high-density spatiotemporal sensing and actuation, as shown in perfused ex vivo hearts.

Bioresorbable electronic stimulators are of rapidly growing interest as unusual therapeutic platforms, i.e., bioelectronic medicines, for treating disease states, accelerating wound healing processes and eliminating infections. Here, we present advanced materials that support operation in these systems over clinically relevant timeframes, ultimately bioresorbing harmlessly to benign products without residues, to eliminate the need for surgical extraction. Our findings overcome key challenges of bioresorbable electronic devices by realizing lifetimes that match clinical needs. The devices exploit a bioresorbable dynamic covalent polymer that facilitates tight bonding to itself and other surfaces, as a soft, elastic substrate and encapsulation coating for wireless electronic components. We describe the underlying features and chemical design considerations for this polymer, and the biocompatibility of its constituent materials. In devices with optimized, wireless designs, these polymers enable stable, long-lived operation as distal stimulators in a rat model of peripheral nerve injuries, thereby demonstrating the potential of programmable long-term electrical stimulation for maintaining muscle receptivity and enhancing functional recovery. Bioresorbable electronic stimulators can deliver electrical stimulation in rodents to enhance functional muscle recovery after nerve injury. Here, the authors present a bioresorbable dynamic covalent polymer that enables reliable, long-lived operation of soft, stretchable devices of this type.

Capabilities for continuous monitoring of pressures and temperatures at critical skin interfaces can help to guide care strategies that minimize the potential for pressure injuries in hospitalized patients or in individuals confined to the bed. This paper introduces a soft, skin-mountable class of sensor system for this purpose. The design includes a pressure-responsive element based on membrane deflection and a battery-free, wireless mode of operation capable of multi-site measurements at strategic locations across the body. Such devices yield continuous, simultaneous readings of pressure and temperature in a sequential readout scheme from a pair of primary antennas mounted under the bedding and connected to a wireless reader and a multiplexer located at the bedside. Experimental evaluation of the sensor and the complete system includes benchtop measurements and numerical simulations of the key features. Clinical trials involving two hemiplegic patients and a tetraplegic patient demonstrate the feasibility, functionality and long-term stability of this technology in operating hospital settings. Uninterrupted monitoring of pressure and temperature at skin interfaces can help to minimize the potential for pressure injuries in hospitalized or bedridden patients. Here, the authors introduce a soft, skin-mountable sensor that can continuously provide readings via antennas mounted under bedding, and demonstrate the functionality and robustness of the devices on patients.

Continuous, real-time monitoring of perfusion after microsurgical free tissue transfer or solid organ allotransplantation procedures can facilitate early diagnosis of and intervention for anastomotic thrombosis. Current technologies including Doppler systems, cutaneous O 2 -sensing probes, and fluorine magnetic resonance imaging methods are limited by their intermittent measurements, requirements for skilled personnel, indirect interfaces, and/or their tethered connections. This paper reports a wireless, miniaturized, minimally invasive near-infrared spectroscopic system designed for uninterrupted monitoring of local-tissue oxygenation. A bioresorbable barbed structure anchors the probe stably at implantation sites for a time period matched to the clinical need, with the ability for facile removal afterward. The probe connects to a skin-interfaced electronic module for wireless access to essential physiological parameters, including local tissue oxygenation, pulse oxygenation, and heart rate. In vitro tests and in vivo studies in porcine flap and kidney models demonstrate the ability of the system to continuously measure oxygenation with high accuracy and sensitivity. Although continuous monitoring of tissue oxygenation is critically important after tissue/organ graft procedures, current technologies have key limitations. Here, the authors develop a miniaturized, minimally invasive, self-anchoring optical probe and demonstrate continuous monitoring of oxygenation in porcine flap and organ models.

Resorbable, implantable bioelectronic devices are emerging as powerful tools to reliably monitor critical physiological parameters in real time over extended periods. While degradable magnesium-based electronics have pioneered this effort, relatively short functional lifetimes have slowed clinical translation. Barrier films that are both flexible and resorbable over predictable timelines would enable tunability in device lifetime and expand the viability of these devices. Herein, we present a library of stereocontrolled succinate-based copolyesters which leverage copolymer composition and processing method to afford tunability over thermomechanical, crystalline, and barrier properties. One copolymer composition within this library has extended the functional lifetime of transient bioelectronic prototypes over existing systems by several weeks–representing a considerable step towards translational devices. Resorbable bioelectronic devices have potential as tools for monitoring physiological parameters, but short functional lifetimes have slowed translation. Here, the authors report succinate-based copolyesters with barrier properties able to extend the functional lifetime of devices.

Physically transient forms of electronics enable unique classes of technologies, ranging from biomedical implants that disappear through processes of bioresorption after serving a clinical need to internet-of-things devices that harmlessly dissolve into the environment following a relevant period of use. Here, we develop a sustainable manufacturing pathway, based on ultrafast pulsed laser ablation, that can support high-volume, cost-effective manipulation of a diverse collection of organic and inorganic materials, each designed to degrade by hydrolysis or enzymatic activity, into patterned, multi-layered architectures with high resolution and accurate overlay registration. The technology can operate in patterning, thinning and/or cutting modes with (ultra)thin eco/bioresorbable materials of different types of semiconductors, dielectrics, and conductors on flexible substrates. Component-level demonstrations span passive and active devices, including diodes and field-effect transistors. Patterning these devices into interconnected layouts yields functional systems, as illustrated in examples that range from wireless implants as monitors of neural and cardiac activity, to thermal probes of microvascular flow, and multi-electrode arrays for biopotential sensing. These advances create important processing options for eco/bioresorbable materials and associated electronic systems, with immediate applicability across nearly all types of bioelectronic studies. Designing and manufacturing eco/bioresorbable electronic systems remains a challenge. The authors introduce a picosecond-pulsed laser-based scheme that exploits controlled patterning, thinning, and/or cutting to manipulate multilayers of eco/bioresorbable materials for a wide range of advanced electronic systems.

Capabilities in real-time monitoring of internal physiological processes could inform pharmacological drug-delivery schedules, surgical intervention procedures and the management of recovery and rehabilitation. Current methods rely on external imaging techniques or implantable sensors, without the ability to provide continuous information over clinically relevant timescales, and/or with requirements in surgical procedures with associated costs and risks. Here, we describe injectable classes of photonic devices, made entirely of materials that naturally resorb and undergo clearance from the body after a controlled operational lifetime, for the spectroscopic characterization of targeted tissues and biofluids. As an example application, we show that the devices can be used for the continuous monitoring of cerebral temperature, oxygenation and neural activity in freely moving mice. These types of devices should prove useful in fundamental studies of disease pathology, in neuroscience research, in surgical procedures and in monitoring of recovery from injury or illness. Bioresorbable photonic devices for the spectroscopic characterization of tissues and biofluids can continuously monitor cerebral temperature, oxygenation and neural activity in the brains of freely moving mice before they are fully resorbed.

Myocardial infarction (MI) is one of the leading causes of death and disability. Recently developed cardiac patches provide mechanical support and additional conductive paths to promote electrical signal propagation in the MI area to synchronize cardiac excitation and contraction. Cardiac patches based on conductive polymers offer attractive features; however, the modest levels of elasticity and high impedance interfaces limit their mechanical and electrical performance. These structures also operate as permanent implants, even in cases where their utility is limited to the healing period of tissue damaged by the MI. The work presented here introduces a highly conductive cardiac patch that combines bioresorbable metals and polymers together in a hybrid material structure configured in a thin serpentine geometry that yields elastic mechanical properties. Finite element analysis guides optimized choices of layouts in these systems. Regular and synchronous contraction of human induced pluripotent stem cell‐derived cardiomyocytes on the cardiac patch and ex vivo studies offer insights into the essential properties and the bio‐interface. These results provide additional options in the design of cardiac patches to treat MI and other cardiac disorders.

Genetic engineering and implantable bioelectronics have transformed investigations of cardiovascular physiology and disease. However, the two approaches have been difficult to combine in the same species: genetic engineering is applied primarily in rodents, and implantable devices generally require larger animal models. We recently developed several miniature cardiac bioelectronic devices suitable for mice and rats to enable the advantages of molecular tools and implantable devices to be combined. Successful implementation of these device-enabled studies requires microsurgery approaches that reliably interface bioelectronics to the beating heart with minimal disruption to native physiology. Here we describe how to perform an open thoracic surgical technique for epicardial implantation of wireless cardiac pacemakers in adult rats that has lower mortality than transvenous implantation approaches. In addition, we provide the methodology for a full biocompatibility assessment of the physiological response to the implanted device. The surgical implantation procedure takes ~40 min for operators experienced in microsurgery to complete, and six to eight surgeries can be completed in 1 d. Implanted pacemakers provide programmed electrical stimulation for over 1 month. This protocol has broad applications to harness implantable bioelectronics to enable fully conscious in vivo studies of cardiovascular physiology in transgenic rodent disease models. This protocol describes how to perform an open thoracic surgery for epicardial implantation of wireless cardiac bioelectronic devices in adult rats and the methodology for a full biocompatibility assessment of the physiological response to the implanted device.

Nanophotonics has revolutionized the control of light-matter interactions in various fields of fundamental science and technology. In this work, we propose Implosion Fabrication (ImpFab) as a versatile nanophotonics fabrication platform providing the highest spatial resolution, material versatility, and full volumetric control. ImpFab uniquely combines top-down lithography with bottom-up nanoparticle assembly within a hydrogel scaffold, enabling precise control over optical material properties, such as refractive index, by adjusting printing parameters. We showcase the potential of ImpFab by fabricating three-dimensional photonic crystals and quasicrystals, as well as demonstrating optical structures with spatially modulated unit cell material properties. Our results highlight the potential of ImpFab in producing nanostructures with tailored optical functionalities, which are crucial for applications in sensing, imaging, and information processing, and opening new avenues in developing non-Hermitian photonic systems with spatially controlled gain and loss. We combine hydrogel photopatterning with nanoparticle growth to form silver-enhanced features that isotropically shrink 1000 × in volume to realize nanoscale 3D structures with tunable optical properties.