The biocompatibility of silk fibroin and acellular collagen scaffolds for tissue engineering in the ear.

Recent experimental studies have shown the suitability of silk fibroin scaffold (SFS) and porcine-derived acellular collagen I/III scaffold (ACS) as onlay graft materials for tympanic membrane perforation repair. The aims of this study were to further characterize and evaluate the in vivo biocompatibility of SFS and ACS compared with commonly used materials such as Gelfoam and paper in a rat model. The scaffolds were implanted in subcutaneous (SC) tissue and middle ear (ME) cavity followed by histological and otoscopic evaluation for up to 26 weeks. Our results revealed that SFS and ACS were well tolerated and compatible in rat SC and ME tissues throughout the study. The tissue response adjacent to the implants evaluated by histology and otoscopy showed SFS and ACS to have a milder tissue response with minimal inflammation compared to that of paper. Gelfoam gave similar results to SFS and ACS after SC implantation, but it was found to be associated with pronounced fibrosis and osteoneogenesis after ME implantation. It is concluded that SFS and ACS both were biocompatible and could serve as potential alternative scaffolds for tissue engineering in the ear.

A review on the use of hyaluronic acid in tympanic membrane wound healing.

INTRODUCTION: Tympanic membrane perforation represents a significant morbidity, especially if it occurs during a child's speech and language development. Recently, there has been an increased interest in hyaluronic-acid-related research and products as a potential therapeutic option for tympanic membrane perforation repair. AREAS COVERED: This review describes the physical and chemical properties of hyaluronic acid and examines the role of hyaluronic acid in wound healing, in particular on the tympanic membrane. It also reviews the safety and efficacy of hyaluronic acid and its derivatives in animal studies as well as in clinical trials. Finally, it considers the potential future clinical applications in tympanic membrane perforation repair. EXPERT OPINION: Hyaluronic acid has been found to accelerate tympanic membrane perforation closure, shorten the period of healing, produce a better quality neo-membrane and improve hearing. More importantly, hyaluronic acid is biodegradable, safe and biocompatible in the ear. Recently, there has been a trend towards the use of modified hyaluronic acid. However, there is a lack of higher-level evidence to support the use of hyaluronic acid in tympanic membrane perforations in the clinical setting. More large-scale randomised control trials are warranted before these bio-devices will be used routinely.