• • Dual electrochemical-ultrasonic architecture achieves minimized signal crosstalk, directly improving multimodal sensing accuracy and stability while maintaining low power consumption—critical for continuous wearability and practical clinical deployment.
• • Biocompatibility and long-term stability remain unresolved: potential skin irritation, sensor degradation, and signal drift during extended wear require chronic skin response assessment to microneedle insertion and mechanical-electrochemical durability testing under repeated physiological stress.
• • Scalability bottlenecks persist in reliable assembly of flexible circuits, power units, and sensing modules on deformable substrates; consistent device performance, batch production yield, and mechanical integrity under deformation are key engineering challenges for clinical translation.
• • Expansion to insulin, cortisol, and β-hydroxybutyric acid would significantly enhance diagnostic coverage, enabling monitoring of glycemic status, stress, hormonal regulation, and ketone metabolism—critical for early screening and refined classification of complex metabolic disorders.