Despite the growth in healthcare technology functionality over the last several decades, the long-term integration of implantable medical devices still depends on a body's immune response at the biotic-abiotic interface. Implanted devices are threatened by the body’s immune response and fibrosis. Currently, soft robotic actuators made from low modulus polymers that match mechanical properties of surrounding organic tissue. While compliance matching addresses part of the problem, the body often responds to implanted synthetics materials with fibrosis. Therefore, progress in soft robotics lies in investigating the surface properties and chemistry of new materials. We hypothesize that soft robotic actuators with a protein base may match surrounding tissues and also provide physiologically relevant chemical cues leading to long term reliability. Protein-based actuators may be more biocompatible than traditional silicone actuators and possibly integrate more naturally with a body's cells and tissue for long-term safety and implant reliability. Furthermore, controlling actuator degradation could have potential for drug delivery systems or support devices post-surgery. In this presentation, we detail our development and characterization of transglutaminase crosslinked gelatin actuators that are stable in physiologically relevant fluid conditions, match the mechanics of target tissues, and hold promise for integration into low modulus medical device designs. By tuning crosslinking ratios and fabrication protocols, we can control properties and functional stability. In this work we characterize the surface features that will promote host integration, porosity in the structures, and degradation kinetics of the actuators. We found in initial testing that a one-step fabrication process, in contrast to a two-step process, was more durable during fatigue testing, which may be due to porosity in the material that protects actuators from shera failures. To test these devices in physiologically relevant solutions, we developed a test rig that allows for real time fatigue testing and analysis of the material mechanics during prolonged use in a simulated in vivo environment. The implementation of soft robots in the fields of tissue engineering and healthcare are further advanced with the progress made in developing biodegradable actuators in place of implantable synthetic materials.

Development and characterization of biostable tendon actuated hydrogel actuators for implantable devices

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.