Project Summary Long-term, continuous monitoring of heart electrical activities via electrocardiogram (ECG) plays a critical role in early diagnosis and timely interventions of various heart diseases. Concurrent detections of heart mechanics via seismocardiogram (SCG) can yield important data that complement ECG with enhanced utility in early detections of cardiac complications. However, existing ambulatory cardiac monitors are often single-modality and can only detect ECG. Moreover, they usually suffer from poor long-term usability because nonporous constituent materi- als limit their user-friendliness and long-term biocompatibility. To overcome these handicaps, this project aims to develop multifunctional porous soft materials and explore their applications in next-generation user-friendly skin-interfaced cardiac patches with bimodality (concurrent ECG and SCG recording) and long-term biocompat- ibility. The central hypothesis is that rationally designed porous constituent materials and judiciously tailored device fabrication process can enable next-generation skin-interfaced wearables with outstanding user-friendli- ness-related properties (e.g., skin-like compliance, high breathability, antimicrobial) without sacrificing their elec- trical performances. Two research aims include i) developing multifunctional porous elastomer with antimicrobial property via phase separation and investigating extrusion printing of silver nanowire-based conductive materials on obtained porous elastomers; and ii) fabricating mobile cardiac monitoring system with porous materials and evaluating its performance via on-body tests. The major innovations include (1) creation of unprecedented mul- tifunctional porous soft materials that can simultaneously achieve skin-like compliance, high breathability, anti- bacterial, and waterproof; (2) establishment of maskless, additive, high-throughput fabrications of bioelectronic devices on porous materials; and (3) generation of novel skin-interfaced cardiac patch that can outperform con- ventional ones in terms of its user-friendliness, long-term biocompatibility, and long-lasting, reliable, concurrent ECG and SCG recording. From a clinical perspective, the enabling cardiac monitoring device can shift the current paradigm of ambulatory cardiac monitoring and benefit the people who suffer from heart diseases by providing unprecedented user-friendliness for patients to wear and collecting real-time, reliable, comprehensive (ECG and SCG) data for physicians to make crucial care decisions. From a fundamental science perspective, the proposed research concerns foundational questions in skin-interfaced wearables: how to improve the user-friendliness and long-term biocompatibility of skin-interfaced wearables via material innovations (e.g., development of multifunc- tional porous soft materials) and how to fabricate high-performance bioelectronics with porous materials. From a technical perspective, the created materials and addressed fabrication principles can be used to construct various customized skin-interfaced wearables with outstanding user-friendliness, long-term biocompatibility, and long-lasting fidelity of biosignals recording to meet a variety of arising requirements of home-based, personalized healthcare (e.g., monitoring of wound healing, sleep, surgical recovery, stress, COVID-19, and elderly falls).

Project Narrative The proposed research is relevant to public health because it centers on developing multifunctional porous soft materials for next-generation user-friendly skin-interfaced cardiac sensing patches with bimodality (concurrent monitoring of heart electrical and mechanical activities) and long-term biocompatibility for early detections and timely interventions of heart diseases. The enabling device is expected to simultaneously achieve skin-like com- pliance, high stretchability, high breathability, antimicrobial property and waterproof, as well as provide long- lasting, continuous, high-fidelity, concurrent measurements of ECG and SCG signals from human chests. The device is superior to existing ambulatory cardiac monitors and will benefit the people who suffer from heart dis- eases by providing unprecedented user-friendliness for patients to wear and collecting real-time, reliable, com- prehensive (ECG and SCG) data for physicians to make crucial care decisions.