## 1 Introduction  
Tissue engineering has been considered as an effective strategy for tissue repair and regeneration, which is an advanced and emerging field that originates from the intersection of biomedical science, materials science, and engineering. Its primary purpose is to repair or replace damaged tissues using biocompatible engineering material [1]. Due to advances in materials science, numerous biomaterials have been developed for use in tissue engineering. These biomaterials possess properties that closely resemble those of natural tissues, providing an optimal environment for the growth and differentiation of tissue cells [2; 3; 4; 5]. Biological tissues such as bones and teeth are composed by organic molecules and inorganic minerals, formed via biomineralization processes, which are a common natural phenomenon that occurs in various living organisms, including bacteria, microorganisms, plants, and animals. These organisms produce minerals in their bodies, leading to crystal formation and playing different roles in different biological systems. By accurately regulating the nucleation, orientation, growth, and assembly of inorganic minerals, organisms can create organic and inorganic composite materials [6; 7]. Thus, it is of great significance to fabricate tissue engineering scaffolds that have a similar organic/inorganic composite structure in biomineralized tissues. Natural mineralized tissues in various plants and animals often exhibit extraordinary strength and toughness, mainly due to their unique hierarchical structure [8]. These structures range from microscopic anisotropic to molecular and atomic-scale crystal units, each contributing to the overall strengthening and toughening of the material [9; 10]. For example, human bones (Figure 1a) exhibit a multi-level composite structure formed by the orderly arrangement of mineralized collagen, which provides essential mechanical support for the body. Through this mineralization process, the strength and toughness of collagen fibers have been significantly enhanced [11; 12; 13]. The joints of the bone consist of a thin, smooth layer of elastic tissue known as articular cartilage. This cartilage consists of four structural layers: the superficial zone, the transitional zone, the radial zone, and the calcified zone. Articular cartilage lubricates the surface and serves as a load-bearing medium over extended periods of time [14; 15]. Similarly, the mantis shrimp (Figure 1b) is famous for its extraordinary hunting ability and incredibly tough exoskeleton, which is composed of highly mineralized chitin fibers and arranged in a spiral layer. This unique structure provides mantis shrimp with extraordinary resistance to pressure and impact, enabling it to hit its prey with great strength and high speed while remaining unscathed. These layered structures provide the mantis shrimp with exceptional compressive and impact resistance [16]. The formation of such specialized tissues relies on the biomineralization process, which involves the production and deposition of minerals within the organism. This process is very complex and involves the sophisticated regulation between cells, proteins, and minerals [17]. Figure 1: The design strategy, preparation process, and microstructural characteristics of chitosan/CaCO\({}_{3}\) composites. (**a**) Schematic diagram illustrating the hierarchical structure of the natural skeleton. (**b**) Schematic representation of the compositional components of the mantis shrimp’s dactyl club. (**c**) Preparation method of the chitosan/CaCO\({}_{3}\) composite hydrogel and a schematic diagram of its structure. To replicate the structure and function of natural mineralized tissues, researchers have developed various methods for preparing ceramic/biopolymer composite materials, including hybridization, electrospinningning, and 3D printing. For instance, [PERSON] et al. [18] incorporated low-crystallinity hydroxyapatite (HAP) particles into a double network (DN) hydrogel system.