A medical adhesive used in a wet environment by blending tannic acid and silk fibroin

A multifunctional and effective medical adhesive with a combination of high toughness and superior adhesion is highly desired in biomedical fields. However, clinical application of medical adhesives is still limited due to their weak adhesion to wet tissue. In this study, a novel medical adhesive called TASK composed of tannic acid (TA) and silk fibroin (SF) based on polyphenol-gel systems was developed. TASK powder was prepared by a simple physical mixture of pyrogallol-rich tannic acid and silk fibroin in aqueous solution and further freeze drying, which was stable and convenient for sterilization before clinical application. The TASK composite gel was formed by just adding water to the TASK powder. TASK showed improved wet-adhesive properties and stability; its adhesion strength after 5 h in water reached 180.9 ± 27.4 kPa. ATR-FTIR results indicated that the plentiful phenolic hydroxyl groups in TA allowed TASK to maintain adhesion to tissue in a wet environment. Furthermore, no chemical modification or covalent cross-linking was required for this wet-adhesive TASK which may facilitate its clinical application.