Mussel-Inspired Cell/Tissue-Adhesive, Hemostatic Hydrogels for Tissue Engineering Applications

The combination of multiple physiological (swelling, porosity, mechanical, and biodegradation) and biological (cell/tissue-adhesive, cell proliferation, and hemostatic) properties on a single hydrogel has great potential for skin tissue engineering. Adhesive hydrogels based on polydopamine (PDA) have become the most popular in the biomedical field; however, integrating multiple properties on a single adhesive hydrogel remains a challenge. Here, inspired by the chemistry of mussels, we developed PDA–sodium alginate–polyacrylamide (PDA–SA–PAM)-based hydrogels with multiple physiological and biological properties for skin tissue engineering applications. The hydrogels were prepared by alkali-induced polymerization of DA followed by complexation with SA in PAM networks. The chemical composition of the hydrogels was characterized by X-ray photoelectron spectroscopy. PDA–SA complexed chains were homogeneously dispersed in the PAM network and exhibited good elasticity and excellent mechanical properties, such as a compressive stress of 0.24 MPa at a compression strain of 70% for 0.4PDA–SA–PAM. The adhesive hydrogel also maintained a highly interconnected porous structure (∼94% porosity) along with PDA microfibrils. The hydrogel possesses outstanding swelling and biodegradability properties. Owing to the presence of the PDA–SA complex in the PAM network, the hydrogels show good adhesion to various substrates (plastic, skin, glass, computer screens, and leaves); for example, the adhesive strength of the 0.4PDA–SA–PAM to porcine skin was 24.5 kPa. The adhesive component of the PDA–SA chains in the PAM network significantly improves the cell proliferation, cell attachment, cell spreading, and functional expression of human skin fibroblasts (CCD-986sk) and keratinocytes. Moreover, the PDA chains exhibited good hemostatic properties, resulting in rapid blood coagulation. Considering their excellent cell affinity, and rapid blood coagulation ability, these mussel-inspired hydrogels have substantial potential for skin tissue engineering applications.