David Clausen

Biophysical signals such as motion and optically acquired hemodynamics represent foundational sensing modalities for wearables. Expansion of this toolset is vital for the progression of digital medicine. Current efforts utilize biofluids such as sweat and interstitial fluid with primarily adhesively mounted sensors that are fundamentally limited by epidermal turnover. A class of potential biomarkers that is largely unexplored are gaseous emissions from the body. In this work, we introduce an approach to capture emission of gas from the skin with a leaky cavity designed to allow for diffusion-based ambient gas exchange with the environment. This approach, coupled with differential measurement of ambient and in-cavity gas concentrations, allows for the real-time analysis of sweat rate, VOCs, and CO₂ while performing everyday tasks. The resulting biosignals are recorded with temporal resolutions that exceed current methodology, providing unparalleled insight into physiological processes without requiring sensor replacement over weeks at a time.

Spinal cord stimulation (SCS) for chronic pain management is an invasive therapy involving surgical implantation of electrodes into spinal epidural space. While the clinical value and mechanistic action of the therapy is debated considerably in recent years, preclinical chronic studies employing rodent models can provide invaluable insights regarding the balance between efficacy and complications as well as mechanistic understanding of SCS therapy. However, current rodent compatible devices require tethered power delivery or bulky batteries, severely limiting the ability to probe long‐term efficacy of SCS therapy. This work introduces a tether‐free, small‐footprint, fully implantable, battery‐free SCS device compatible with rodent models, capable of delivering electrical stimulation to the spinal cord at a wide range of frequency, amplitude, and period via wireless communication adjustable on‐demand without direct interaction with the animal. The presented device features capabilities of clinical SCS devices, with materials and processes amendable to scalable fabrication at a cost suitable for one‐time use enabling high N studies. In this proof of concept, the implantable device serves to assess therapeutic efficacy of various clinically relevant SCS paradigms in alleviating neuropathic pain. This technology offers chronic stability and the potential to serve as the foundation for future research into the development of SCS therapeutic systems.

Continuous monitoring of electrophysiological biosignals such as electrocardiogram (ECG) and bioimpedance (BioZ) rely on gel‐based electrodes and adhesive skin interfaces requiring active patient interaction inherently restricting chronic use. Current solutions aimed at addressing seamless, comfortable, and reliable recordings with dry electrodes use battery power and are limited to days of operation with clinical‐grade fidelity. Here, current limitations are overcome by uniting at‐distance wirelessly powered wearable electronics with carbon‐doped filament deposition modeling (FDM) printed dry electrodes that overcome impedance degradation by seamless integration into textile and biosymbiotic systems, allowing for high‐fidelity operation over indefinite timescales. These capabilities are demonstrated with ECG during work, activity, and sleep and BioZ recordings documenting gains in forearm training over weeks.

Remote patient monitoring is a critical component of digital medicine, and the COVID-19 pandemic has further highlighted its importance. Wearable sensors aimed at noninvasive extraction and transmission of high-fidelity physiological data provide an avenue toward at-home diagnostics and therapeutics; however, the infrastructure requirements for such devices limit their use to areas with well-established connectivity. This accentuates the socioeconomic and geopolitical gap in digital health technology and points toward a need to provide access in areas that have limited resources. Low-power wide area network (LPWAN) protocols, such as LoRa, may provide an avenue toward connectivity in these settings; however, there has been limited work on realizing wearable devices with this functionality because of power and electromagnetic constraints. In this work, we introduce wearables with electromagnetic, electronic, and mechanical features provided by a biosymbiotic platform to realize high-fidelity biosignals transmission of 15 miles without the need for satellite infrastructure. The platform implements wireless power transfer for interaction-free recharging, enabling long-term and uninterrupted use over weeks without the need for the user to interact with the devices. This work presents demonstration of a continuously wearable device with this long-range capability that has the potential to serve resource-constrained and remote areas, providing equitable access to digital health.

Monitoring and control of cardiac function are critical for investigation of cardiovascular pathophysiology and developing life-saving therapies. However, chronic stimulation of the heart in freely moving small animal subjects, which offer a variety of genotypes and phenotypes, is currently difficult. Specifically, real-time control of cardiac function with high spatial and temporal resolution is currently not possible. Here, we introduce a wireless battery-free device with on-board computation for real-time cardiac control with multisite stimulation enabling optogenetic modulation of the entire rodent heart. Seamless integration of the biointerface with the heart is enabled by machine learning–guided design of ultrathin arrays. Long-term pacing, recording, and on-board computation are demonstrated in freely moving animals. This device class enables new heart failure models and offers a platform to test real-time therapeutic paradigms over chronic time scales by providing means to control cardiac function continuously over the lifetime of the subject.