Fabrication of biocompatible chitin-derived dual-network nanocomposite hydrogels with antibacterial and blood coagulation properties / Juanni Zhang

Faculty of Chemical and Process Engineering Technology

Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2025

Includes bibliographical references

Chitin, the second most abundant natural polysaccharide after cellulose, is a renewable biopolymer composed of β-(1→4)-linked N-acetylglucosamine units. Despite its excellent biocompatibility, degradability, and modifiability, the practical application of chitin remains limited by its poor solubility. Chemical modification can significantly enhance chitin's solubility and functionality, facilitating the research and development of chitin-derived hydrogels. However, chitin-derived hydrogels still encounter challenges such as insufficient mechanical strength, poor biocompatibility, and limited antibacterial properties. To address the limitations, this study integrates dual-network and nanocomposite technologies to develop chitosan/HAp@Zn dual-network nanocomposite hydrogels and quaternized chitosan/chitin nanowhisker dual-network nanocomposite hydrogels, aiming to enhance their properties and broaden their potential applications. The former comprises chitosan, zinc-loaded nano-hydroxyapatite (HAp@Zn), acrylylglycine (ACG), and N-benzylacrylamide (NBAA), while the latter consists of quaternized chitosan (QCS), chitin nanowhiskers (ChWs), acrylic acid, acrylamide, and Zn²+. The influence of the concentration of each component on the properties of the hydrogel was investigated by one-factor-at-a-time analysis, and the structure of the hydrogel was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Additionally, the physical properties (mechanical strength, swelling property, rheological behavior) and biological properties (antibacterial, cytotoxicity, hemolysis, blood coagulation) were systematically examined. The results indicate that the chitosan/HAp@Zn hydrogel possesses excellent mechanical strength and pH-responsive swelling performance. Its maximum mechanical strength is 495.2 kPa and its equilibrium swelling rate is 23.4g/g. The maximum antibacterial rates of E. coli and S. aureus reached 100% and 99.9% respectively. These hydrogels are not cytotoxic and can demonstrate excellent blood compatibility by adjusting their composition. Additionally, they were found to have a good ability for blood coagulation. For the QCS/ChWs hydrogels, the maximum mechanical strength and equilibrium swelling rate are 391.9 kPa and 59.0 g/g, respectively. The maximum antibacterial rates of E. coli and S. aureus were as high as 99.7%. Furthermore, they exhibit superior blood compatibility and no cytotoxicity as well. Most importantly, they show the ability to clot blood rapidly. This study significantly improves the comprehensive properties of chitin-derived hydrogels. It provides an important theoretical basis and technical support for its application in tissue engineering, antibacterial, and hemostatic materials.