Fabrication Of Conductive,Stimuli-Responsive And Anti-Bacterial Multi-Functional Elastomer And Its Orthopaedic Applications

The most common application of hydrogel materials in orthopaedic surgery is wound dressing for the treatment of avulsion injury,large-area skin abrasions,crush injury,etc.Wearable medical devices based on multi-functional sensors have also attracted considerable attention with the emergence of concepts such as "intelligent healthcare".However,there are some inherent drawbacks in the commonly used wound dressing materials and sensors for wearable devices.Therefore,this work reported a simple fabrication route of a novel multi-functional elastomer(MFE)based on the mixture of starch hydrogel and polydimethylsiloxane(PDMS).Meanwhile,the structure and properties of MFE were studied and its potentials as wound dressing and multi-functional sensors were also explored.MFE is injectable,flexible and conductive.And a series of approaches was used to regulate the properties and to obtain a "customized" MFE.The concentration of electrolyte,the ratio of starch hydrogel to PDMS and the electrolyte types can be adjusted or altered to regulate its stretchability(110%-420%),tensile strength(0.12 MPa-0.22 MPa),compressive strength(0.35 MPa-1.5 MPa under 70% compressive strain),contact angle(18°-113°)and humidity sensitivity(monitoring range).Based on the requirements of clinically ideal wound dressing materials,the biocompatibility,anti-bacterial performance and stickiness of MFE were systematically studied.The biocompatibility of MFE was assessed by culturing fibroblasts and human umbilical vein endothelial cells(HUVECs)in the soluble extract of MFE and seeding HUVECs on the surface of MFE directly.The RGR(Relative Growth Rate)of HUVECs and fibroblasts cultured in the soluble extract of MFE respectively reached 126.4% and 107.6% on the 3rd day,indicating nontoxicity of MFE to fibroblasts and HUVECs.Besides,MFE could eliminate >94.2% of S.aureus and >99.9% of E.coli that were seeded on MFE directly,revealing a capability of protecting the wounds from infection.In addition,HPE was self-sticky so that it could adhere to the wound surface without additional adhesive.The capability to absorb fluid could effectively prevent wound maceration through the absorption of effusion.A customized MFE with a capability to sense strain,stress,changing humidity and temperature was fabricated to detect the force condition,humidity and temperature of micro-environment around wounds,which could be further used for monitoring wound healing and postoperative rehabilitation instruments.Additionally,the potential of MFE in the environment sensing,motion detection,force sensing and control of robotic arms was also demonstrated.