Highly sensitive and antibacterial flexible bilayer strain biosensor for human motion monitoring

Developing a strain sensor with high sensitivity, response stability, and excellent antibacterial performance has received increasing attention in the fields of postoperative motion monitoring and medical diagnosis. Herein, a bilayer structure biosensor with excellent antibacterial, self-healing properties, and response sensitivity was design. The lower layer of the sensor was composed of Cetyltrimethylammonium bromide (CTAB) grafted vegetable oil-based polymer, and the conductive layer was sodium carboxymethylcellulose-coated Carbon nanotubes (CNTs) gel. The bilayer structure sensor exhibited excellent self-healing, response stability, and electromechanical response sensitivity, the gauge factor (GF) could reach up to 27.49, which is better than most reported strain sensors. Furthermore, the assembled sensor had remarkable response behaviour to fingers, elbow bending, and pulse beats. Due to the synergistic antibacterial between CNTs and CTAB, the composite demonstrated excellent antibacterial performance against Escherichia coli and Staphylococcus aureus, and antibacterial rates were over 97.74%. Based on these advantages, the obtained strain sensor is expected to have valuable application potential in the field of postoperative motion monitoring.