Bio-inspired flexible pressure sensors: morphology-guided structure–function relationships, reliability, and future perspectives

Bio-inspired flexible pressure sensors have emerged as a major class of soft sensing systems for wearable electronics, electronic skin, human–machine interfaces, and soft robotics because biological structures provide effective design principles for regulating deformation, contact evolution, and interfacial adaptation. However, the field remains difficult to compare critically because reported performance is often discussed through isolated sensitivity values, while the structural origins of signal generation, the pressure-regime dependence of response, and the reliability limits of the underlying architectures are not examined in a unified manner. This review addresses that gap through a morphology-centered perspective, in which bio-inspired pressure sensors are analyzed according to the engineered structural motifs that govern their function. Surface-relief and contact-engineered architectures, porous and three-dimensional frameworks, interfacial, interlocking, and adhesive systems, and hierarchical or discontinuity-driven designs are examined in relation to their coupling with piezoresistive, capacitive, iontronic, triboelectric, piezoelectric, and hybrid transduction pathways. Across these classes, sensitivity, operating range, dynamic response, hysteresis, drift, durability, and failure behavior are traced to the pressure-responsive structural features that define each architecture. This analysis further shows that features designed to amplify signal often also set the boundaries for reversibility and long-term stability. Finally, current challenges in benchmarking and validation are discussed, with emphasis on the need for morphology-traceable reporting, realistic reliability assessment, and structure-guided design rules for future bio-inspired flexible pressure sensors.