Therapeutic Ultrasound Triggered Silk Fibroin Scaffold Degradation

A patient's capacity for tissue regeneration varies based on age, nutritional status, disease state, lifestyle, and gender. Because regeneration cannot be predicted prior to biomaterial implantation, there is a need for responsive biomaterials with adaptive, personalized degradation profiles to improve regenerative outcomes. This study reports a new approach to use therapeutic ultrasound as a means of altering the degradation profile of silk fibroin biomaterials noninvasively postimplantation. By evaluating changes in weight, porosity, surface morphology, compressive modulus, and chemical structure, it is concluded that therapeutic ultrasound can trigger enhanced degradation of silk fibroin scaffolds noninvasively. By removing microbubbles on the scaffold surface, it is found that acoustic cavitation is the mechanism responsible for changing the degradation profile. This method is proved to be safe for human cells with no negative effects on cell viability or metabolism. Sonication through human skin also effectively triggers scaffold degradation, increasing the clinical relevance of these results. These findings suggest that silk is an ultrasound-responsive biomaterial, where the degradation profile can be adjusted noninvasively to improve regenerative outcomes.