A flexible, smart and self-evolving actuator based on polypropylene mesh for hernia repair and a thermo-sensitive gel

Here, a smart mesh actuator, able to self-evolve under temperature and humidity control,has been developed. Thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm)-based materialsare widely appliedin biomedical field owingto theirexcellent biocompatibility and abrupt conformational change at a critical temperature very close to that of human body(~32 °C) [1-2]. The actuator is based on PNIPAAmgrafted on a commercial polypropylene (PP)mesh used for hernia repair[3].Flexible devices composed of PP-g-PNIPAAm arranged inmonolayer (one layer of PNIPAAm) and bilayer (two layers of PNIPAAm) conformationswere synthesized. The microstructureof the gel chains (chain length measurements) and the macromotion(unfolding angle observations) behavior of the composite mesh in water and air at different temperatures were studied. The motion is affected by the amount and the position of the gel (upper fibers or among them) and by the crosslinking degree. For the first time,a self-evolving motion sensor based on commercial hernia repair mesh has beenproduced by using a biocompatible hydrogel. The strategy can be easily extrapolated to complex mesh architectures