High-performance wearable pressure sensors based on biocompatible 3D-printed PU sponges with MXene coating

This study presents the development of piezoresistive pressure sensors based on Ti 3 C 2 T x MXene-coated polyurethane (PU) sponges fabricated using Digital Light Processing (DLP) 3D printing. Six different porous structures were designed by varying the line width (300 and 500 μm) and height width (100, 300, and 500 μm) to optimize the sensor performance. The 500 × 300 μm structure demonstrated an optimal balance between sensitivity and measurement range, achieving resistance change rates from −11.02 % at 25 Pa to −163.78 % at 2.25 kPa. DLP 3D printing allows precise control of pore geometry with dimensional accuracy within 50 μm, while eliminating the complex multistep fabrication processes associated with traditional template methods. The sensor exhibited excellent durability, with less than 1.5 % performance variation after 1000 compression cycles at both 1 and 2 kPa values. Environmental stability tests revealed minimal interference from humidity (30–90 % RH) and predictable temperature-dependent behavior (20–90 °C). Cytotoxicity assessments using RAW 264.7 macrophages confirmed biocompatibility, with cell viability exceeding 95 % for both MAX/MXene materials and PU/MXene composites. Practical demonstrations, including finger pressing, palm contact, and dynamic tapping, validated the capability of the sensor for human motion detection. The combination of DLP 3D printing precision and MXene conductivity enables the scalable production of customizable pressure sensors for wearable electronics, health monitoring, and human–machine interface applications.