Existing surgical tissue adhesives on the market cannot meet the desired demand for clinical operations due to their limited adhesivity or undesired cytotoxicity. A new bioadhesive is derived from the skin secretion of Andrias davidianus (SSAD). This bioinspired SSAD has significantly stronger tissue adhesion than the fibrin glue and improved elasticity and biocompatibility when compared to the cyanoacrylate glue both ex vivo and in vivo. Additionally, the SSAD‐based adhesive decreases skin wound healing time and promotes wound regeneration and angiogenesis. The SSAD‐based adhesive is completely degradable, strongly adhesive, and easily produced from a renewable source. Based on these favorable properties, the SSAD‐based bioadhesive demonstrates potential as a surgical bioadhesive for a broad range of medical applications.

disorders, can cause significant morbidities and mortalities in almost all populations. Uncontrolled bleeding is considered a primary cause of death outside of the hospital, where exsanguination is one of the predominant causes of post-traumatic death, accounting for 12.5-26.6%. [1] One study on combat casualty indicates that 24% of deaths are potentially preventable and are related to delayed or lack of hemorrhage control. [2] Effective and rapid control of hemorrhage can significantly reduce death rates and save lives. Hemostasis is the first step of wound healing and is of great significance. [3] However, without the help of hemostatic devices and agents, especially in emergency and severe situations, self-coagulation alone cannot achieve timely hemostasis.Thus, multiple hemostatic powders (e.g., silicates, chitosan, zeolites, polysaccharides, coagulation proteins, and some traditional Chinese medicines (TCMs) [4] aiming to control blood loss have also been developed. Among them, silicates [5] have already been widely used in warfare due to their outstanding absorption capability, which condense coagulation factors and allow negative charge-enabled activation of the intrinsic coagulation pathway. [6] However, silicates can generate cytotoxicity and even thrombotic events in vivo, and thus the United States Food High-performance hemostasis has become increasingly essential in treating various traumas. However, available topical hemostats still have various drawbacks and side-effects. Herein, hemostatic powders derived from the skin secretion of Andrias davidianus (SSAD) with controllable particle size are prepared using feasible frozen-ball milling following lyophilization for hemorrhage-control. Scanning electron microscopy, rheometry, and Brunauer-Emmett-Teller test are used to characterize the coagulationpromoting surface topography, rheological properties, and porous structure of the SSAD particles. The blood-coagulation assays showed that the SSAD powders can induce blood-absorption in a particle size-dependent manner. Particle sizes of the SSAD powders larger than 200 µm and smaller than 800 µm greatly affect the blood-clotting rate. Associated with the thromboelastography (TEG) and amino acid/protein composition analyses, the accessibility and diffusion of blood are mainly dependent on the wettability, adhesivity, and clotting factors of the SSAD particles. Rapid hemostasis in vivo further involves three hemorrhage models (liver, femoral artery, and tail) as well as an oral wound model, which suggest favorable hemostatic and simultaneous regenerative effects of the SSAD hemostatic powder. Considering its degradability and good biocompatibility, SSAD can be an optimal candidate for a new class of inexpensive, natural, and promising hemostatic and wound-dressing agent.

Tendon regeneration and reduction of peritendinous adhesion remain major clinical challenges. This study addresses these challenges by adopting a unique hydrogel derived from the skin secretion of Andrias davidianus (SSAD) and taking advantage of its biological effects, adhesiveness, and controllable microstructures. The SSAD‐derived hydrogel contains many cytokines, which could promote tendon healing. In vitro, leach liquid of SSAD powder could promote tendon stem/progenitor cells migration. In vivo, the SSAD‐derived hydrogel featuring double layers possesses strong adhesiveness and could reconnect ruptured Achilles tendons of Sprague‐Dawley rats without suturing. The intimal SSAD‐derived hydrogel, with a pore size of 241.7 ± 21.0 µm, forms the first layer of the hydrogel to promote tendon healing, and the outer layer SSAD‐derived hydrogel, with a pore size of 3.3 ± 1.4 µm, reducing peritendinous adhesion by serving as a dense barrier. Additionally, the SSAD‐derived hydrogel exhibits antioxidant and antibacterial characteristics, which further contribute to the reduction of peritendinous adhesion. In vivo studies suggest that the SSAD‐derived hydrogel reduces peritendinous adhesion, increases collagen fiber deposition, promotes cell proliferation, and improves the biomechanical properties of the regenerated tendons, indicating better functional restoration. The SSAD‐derived bilayer hydrogel may be a feasible biomaterial for tendon repair in the future.