Silk fibroin-gelatin films crosslinked by genipin for regenerating tympanic membrane perforations

Abstract

The tympanic membrane (TM) integrity is necessary for our normal hearing function. TM perforations pose significant morbidities such as middle ear infection, recurrent otorrhea, hearing loss, and acquired cholesteatoma. Myringoplasty is commonly performed to repair chronic perforations; although various grafts and materials have been utilized to promote TM regeneration, all have associated restrictions. This study aimed to prepare and evaluate the efficacy and feasibility of a tissue-engineered patch based on silk fibroin and gelatin (SF-GT) to improve regeneration. A casting technique was used to make the SF-GT films, using 0–30 v/v% GT, as it is shown that films are remarkably efficient for TM regeneration, easy to mass produce and cheap to make. The surface morphology (SEM), chemical structure (FTIR), crystallinity (XRD), mechanical strength (tensile test), water uptake and in vitro degradation, and cellular biocompatibility (MTT and scratch) were investigated for SF-GT films, and the optimal patch was chosen based on the results (SF-30GT). SF-30GT was used for in vivo studies in a rat model with TM perforations to induce TM regeneration. The morphology of the TM was assessed at days 0, 3, 5, 7, 9 and 11 post-implantation using otoscopy and functional outcomes by auditory brainstem responses (ABRs). This study indicates that compared with the control group (spontaneous healing), the SF-30GT scaffold was more effective in promoting early TM regeneration (complete healing at day 7) and normal hearing (back to 20 dB after healing), suggesting that this scaffold can be a potential substitute for clinical use.