Recent Advances in 3-D Printed, Wearable Pressure Sensors for Plantar Pressure Monitoring: A Review

Plantar pressure has attracted extensive research interest as a crucial parameter in the assessment of foot and ankle functions during physical activities and in the monitoring and prevention of pressure-related foot diseases. The utilization of 3-D printed pressure sensors, known for their customization, exceptional precision, and flexibility, holds immense potential in wearable in-shoe systems. However, a comprehensive summary and comparison of these 3-D printed, wearable pressure sensors in terms of their printing methods, sensing mechanisms, materials, and structures is still lacking. This article aims to summarize recent research developments and provide insights into the theoretical foundations and essential aspects of 3-D printed pressure sensors dedicated to plantar pressure monitoring. First, typical 3-D printing methods for pressure sensor fabrication are introduced. Second, pressure-sensing mechanisms are summarized from the perspectives of their working principles, 3-D printing materials, and structures. Third, case studies of practical applications in various fields are discussed. Next, the challenges and suggestions for the development of printed pressure sensors for future improvements are addressed. Finally, a conclusion is drawn, offering an outlook on future research directions.