Alginate (Alg) hydrogels have attracted extensive attention in the biomedical field due to their biocompatibility. However, single Alg hydrogels exhibit weak mechanical strength, poor stability and cell adhesion, which severely restricts their biomedical application. For this reason, we designed alginate/gelatin/cellulose nanocrystals (Alg/G/CNCs) composite hydrogels by combining interpenetrating network (IPN) technology, cellulose nanocrystals (CNCs) reinforcement and in situ cross-linking method to improve the functional defects of Alg hydrogels. The structure and properties of the resultant Alg/G/CNCs composite hydrogels were comprehensively evaluated by FT-IR, TGA, XRD, swelling and degradability measurements, and cytocompatibility experiments. Alg/G/CNCs composite hydrogels with regular three-dimensional porous network (3D) structures was successfully fabricated through the ionic cross-linking of alginate and the covalent cross-linking of gelatin, followed by the reinforcement of colloidal cellulose nanocrystals (CNCs) that were prepared by sulfuric acid hydrolysis of microcrystalline cellulose (MCC). The addition of CNCs could generate interaction force with the polymer in the IPN matrix, which was able to regulate the physicochemical properties of the composite hydrogel to a certain extent. Moreover, with the increase of gelatin (G) content, the compressive strength of Alg/G/CNCs composite hydrogels gradually increased, while the swelling property decreased gradually. Meanwhile, Alg/G/CNCs composite hydrogels exhibited good cell adhesion, proliferation and differentiation properties. In particular, Alg/0.5G/CNCs composite hydrogels displayed the best cell proliferation effect, while Alg/2G/CNCs composite hydrogels revealedthe most significant cell differentiation effect. Therefore, Alg/G/CNCs composite hydrogels could exhibit good mechanical properties and biocompatibility, which possessed great application potential in the field of tissue engineering.

海藻酸盐（Alg）水凝胶由于其生物相容性而在生物医学领域引起了广泛关注。然而，单一的Alg水凝胶机械强度弱、稳定性和细胞粘附性差，严重限制了其生物医学应用。为此，我们结合互穿网络（IPN）技术、纤维素纳米晶（CNCs）增强和原位交联方法设计了海藻酸盐/明胶/纤维素纳米晶（Alg/G/CNCs）复合水凝胶，以改善Alg的功能缺陷。水凝胶。通过FT-IR、TGA、XRD、溶胀和降解性测量以及细胞相容性实验对所得Alg/G/CNCs复合水凝胶的结构和性能进行了综合评价。通过海藻酸盐的离子交联和明胶的共价交联，成功制备了具有规则三维多孔网络（3D）结构的Alg/G/CNCs复合水凝胶，然后通过胶体纤维素纳米晶体（CNCs）进行增强，由微晶纤维素（MCC）经硫酸水解制备。CNC的添加可以与IPN基质中的聚合物产生相互作用力，从而在一定程度上调节复合水凝胶的理化性能。此外，随着明胶（G）含量的增加，Alg/G/CNCs复合水凝胶的抗压强度逐渐增加，而溶胀性能逐渐下降。同时，Alg/G/CNCs复合水凝胶表现出良好的细胞粘附、增殖和分化特性。其中，Alg/0.5G/CNCs复合水凝胶表现出最佳的细胞增殖效果，而Alg/2G/CNCs复合水凝胶则表现出最显着的细胞分化效果。因此，Alg/G/CNCs复合水凝胶具有良好的机械性能和生物相容性，在组织工程领域具有巨大的应用潜力。