Chitosan- and heparin-based advanced hydrogels: their chemistry, structure and biomedical applications

Chitosan and heparin are two biopolymers with different properties that can be combined to develop biomaterials with unique and desirable characteristics. Chitosan is a cationic polymer with antimicrobial, hemostatic, and wound-healing properties. Heparin is an anionic polymer with anticoagulant properties. The combination of chitosan and heparin can be used to develop biomaterials with a variety of applications, including drug delivery, wound dressing, and tissue engineering. These biomaterials can be fabricated into various forms, such as films, membranes, sponges, hydrogels, nanoparticles, and scaffolds. Chitosan is a natural polysaccharide, present in the form of copolymers of N-acetyl-D-glucosamine as repeating units. Heparin is a natural glycosaminoglycan; a linear sulfated molecule consisting of repetitive units of disaccharide containing uronic acid and N-acetyl glucosamine. Heparin binds and activates the vascular endothelial growth factor (VEGF), which in turn promotes proliferation and migration and thus results in angiogenesis and the formation of new blood vessels. These advantages make chitosan- and heparin-based biomaterials promising candidates for a variety of biomedical applications. However, there are still some challenges that need to be addressed before these biomaterials can be widely used in clinical practices. For example, the degradation rate of chitosan- and heparin-based biomaterials need to be better controlled, and the mechanical properties of these biomaterials need to be improved. Despite these challenges, chitosan- and heparin-based biomaterials have the potential to revolutionize the field of biomedicine. These biomaterials offer several advantages over traditional materials, and they have the potential to be used in a variety of innovative applications. The purpose of this review is to provide a comprehensive overview of the current state of research and applications in this field. It aims to summarize the key findings and advancements in the development and use of chitosan- and heparin-based hydrogels for various biomedical applications.