Flexible and Wearable Bioelectronics for Electrocardiography Monitoring: A Review
Cardiovascular diseases account for approximately one-third of global mortality, necessitating continuous electrocardiography (ECG) monitoring for early diagnosis. Traditional clinical ECG systems using rigid metal electrodes or Ag/AgCl gel electrodes suffer from mechanical mismatch, motion artifacts, gel desiccation, and skin irritation, limiting their efficacy in ambulatory settings. This review examines recent advances in flexible and wearable bioelectronics for ECG monitoring across three domains: materials, structural design, and system integration. Emerging functional materials—liquid metals, nanomaterials, and conductive hydrogels—enhance electrical performance and user comfort. Structural strategies including microneedle arrays, bioinspired geometries, and stretchable interconnects improve skin-electrode interface stability and motion adaptability. System-level integration of multichannel and multimodal sensing with wireless transmission supports practical ECG applications. Key experimental benchmarks from the literature include: bioinspired dry adhesives achieving 4770–4778 cm² V⁻¹ s⁻¹? (reference 99), skin-conformal polymer electrodes for clinical ECG/EEG (reference 100), and kirigami-structured low-impedance electronics for long-term biopotential monitoring (reference 107). Despite progress, challenges persist in long-term reliability, data security, and material–structure co-optimization. Future directions include AI-assisted analysis and integrated intelligent ECG monitoring systems. This review provides a critical assessment of the field's trajectory, emphasizing the need for standardized performance metrics and clinical validation to transition from laboratory prototypes to commercialized wearable ECG devices.