A Coenzyme-Based Deep Eutectic Supramolecular Polymer Bioadhesive

Abstract

α-lipoic acid (LA), a coenzyme, has proved to have excellent antioxidant and antibacterial activities; however, its intrinsic hydrophobicity and metastability of polyLA remains a major challenge for the application of LA-based bulk materials in biomedical field. Herein, a self-stabilized LA-based deep eutectic supramolecular polymer (LA-DESP) adhesive is created by one-step heating the mixture of LA and sodium α-lipoate (LA-Na) (S-, R-isomer, racemate) without introducing any exogenous stabilizing molecules. The underlying deep eutectic effect in LA/LA-Na is unveiled to be originated from the multiple hydrogen bonds between polyLA and polyLA-Na, which not only prevent polyLA depolymerization but also lower the melting point of LA-DESP to the near body and pathological temperature. Copolymerization of LA and LA-Na slows down the dissociation of polyLA-Na, thus affording sustainable release of bioactive LA-based small molecules and satisfactory antioxidant and antibacterial functions. Also, the LA-DESP exhibits fast and tough adhesion to diverse substrates, including wet tissues, relying on its in situ curing property and rich carboxyl groups. The LA-DESP is explored as a tissue sealant, which can well replace surgical suture to enhance the wound healing of skin incision in a rat model. The unprecedented deep eutectic effect will provide a new strategy for the development of LA-based bioadhesives.