Anionic Polysaccharides: Promising 3D Bioink Candidates for Tissue Engineering

Anionic polysaccharides are sugars with a negative charge. Common examples include alginic acid, hyaluronic acid, pectin, chondroitin sulfate, and heparin. These molecules are bioactive and widely used in medicine, food, and cosmetics. On their own, they usually do not bind to cells. However, they can serve as bioinks or as parts of bioink mixtures. In 3D bioprinting, anionic polysaccharides are often combined with natural polymers like collagen or with synthetic materials to form hydrogels. These hydrogels act as scaffolds that give cells a three-dimensional space to grow and form tissue. The properties of these hydrogels can be tuned to match specific needs. Together, anionic polysaccharides and 3D bioprinting offer strong potential for tissue engineering, making it possible to build complex, custom tissue structures that may help solve problems in organ repair and replacement. This review summarizes the sources, structures, and key properties of Common anionic polysaccharides, with a comparative analysis of their chemical, biological, and mechanical characteristics and recent 3D printing strategies. It highlights the advantages of anionic polysaccharide bioinks, particularly their compatibility with enzymatic, photo-, and ionic crosslinking, and presents representative examples demonstrating their suitability for diverse tissue engineering applications and printing requirements.