Multiple stimuli-response strategy for on-demand degradable implants: Tannic acid-intercalated polycaprolactone

The versatile potential of polycaprolactone (PCL) as degradable implant materials has been wildly studied. Nevertheless, it is still elusive to tailor the degradation rates as well as the evolution of the mechanical performance in vivo. Taking into account the implant materials require different performance as the stage goes on, this work conceived a novel degradation strategy possessing multiple-stimuli response degradation capability, through incorporating tannic acid (TA) as the cross-linking agent into PCL via facile condensation polymerization. The water contents and degradation rates of the PCL-co-TA composite increased with the increase of TA content. Besides the degradation stimulated by reactive oxygen species (ROS), the PCL-co-TA composite shows accelerated degradation in neutral and basic solution with obvious surface erosion and continuous mass loss within 90 days, however, its mechanical properties maintain stable during this period. Moreover, the PCL-co-TA composite shows controllable drug release capacity with linear release for over 40 days and stable antimicrobial properties for both E.coli and S.aureus. This work provides a novel principle to design degradable implant materials with on-demand degradation behavior. The PCL-co-TA composite shows advanced specificity, sensitivity and diversity of controlling the degradation, demonstrates the great potential applications for tissue engineering and intelligent medicine device.