Title Page

ABSTRACT

Contents

List of Abbreviations 12

Chapter 1. General Introduction 15

1.1. Universal Biomedical Market for Wound Management 15

1.1.1. Importance and Diversity of Wound Management Biomaterials 17

1.1.2. The Wound Healing Process 20

1.2. Bioactive Hydrogels 23

1.2.1. Immunomodulatory Biomaterials for Wound Healing 25

1.2.2. Current Strategies of Immunomodulatory Biomaterials 28

1.3. Inorganic Ion-based Biomaterials 31

1.3.1. Inorganic Ions for Immune Modulation 33

1.3.2. Zinc Ion (Zn²⁺) for Immune Modulation 35

1.3.3. Zn²⁺-releasing Hydrogels Immunomodulatory Mechanism 38

1.4. Research Motivation and Approaches 40

Chapter 2. Zn²⁺-releasing Immunomodulatory Hydrogels 42

2.1. Introduction 42

2.2. Experimental Section 44

2.2.1. Materials 44

2.2.2. Synthesis and Characterization of GtnSH and GtnMI Polymer 45

2.2.3. Preparation of Zn²⁺-releasing Hydrogels and Phase Transition Time 47

2.2.4. Rheological Analysis of Zn²⁺-releasing Hydrogels 49

2.2.5. Releasing Kinetics of Zn²⁺ and H₂O₂ 49

2.2.6. Cytocompatibility of Zn²⁺-releasing Hydrogels 50

2.2.7. In Vivo Subcutaneous Implantation 50

2.2.8. In Vivo Gene Expression Test 51

2.2.9. In Vivo Wound Healing 54

2.2.10. Histological Analysis and Immunofluorescence Staining 54

2.2.11. Statistical Analysis 55

2.3. Results and Discussion 56

2.3.1. Fabrication and Characterization of Zn²⁺-releasing Hydrogels 56

2.3.2. Release Kinetics of Zn²⁺ and H₂O₂ 60

2.3.3. Cyto-, Tissue Compatibility of Hydrogels 63

2.3.4. In Vivo Macrophage Recruitment and M2 Polarization Effect 65

2.3.5. In Vivo Cell Proliferation and Angiogenesis Effect 68

2.3.6. In Vivo Wound Healing (Critical Skin Defect Model) 70

Chapter 3. Conclusion and Future Direction 73

References 74

국문초록 92

Table 1.1. Current wound dressing materials 19

Table 2.1. The hydrogels composition 48

Table 2.2. Primers sequences used in the qRT-PCR analysis 53

Fig. 1.1. Global wound care market overview with Ref. 16

Fig. 1.2. Schematic representation of wound management materials. Redesigned with permission from [14, 15]. Copyright (2022) Elsevier. 18

Fig. 1.3. Schematic of wound healing process in skin. (a) Hemostasis. (b) Inflammation. (c) Proliferation. (d) Remodeling. Redesigned with permission from [23, 24]. Copyright (2020) The... 22

Fig. 1.4. Schematic of bioactive hydrogels with synthetic and natural polymers. Redesigned with permission from [11]. Copyright (2021) Royal Society of Chemistry. Redesigned with permission... 24

Fig. 1.5. Design strategy for immunomodulatory biomaterials to overcome implant rejection. Functional and phenotypic regulation of macrophages. Redesigned with permission from [49].... 27

Fig. 1.6. Current strategy for immunomodulatory biomaterials to modulate macrophage phenotype with biophysical properties and biochemical properties. Redesigned with permission... 30

Fig. 1.7. Effects of various inorganic ion-based biomaterials that directly or indirectly affect cellular function. Redesigned with permission from [82]. Copyright (2020) American Chemical Society. 32

Fig. 1.8. Zinc for the development and function of the immune system, including both innate and adaptive immune cells. Redesigned with permission from [108]. Copy right (2017)... 37

Fig. 1.9. Schematic representation of our approach to design Zn²⁺-releasing hydrogels. The hydrogel network is formed through disulfide bonds via thiol-ene reaction and ZnO₂-mediated... 41

Fig. 2.1. Synthesis and characterization of Zn²⁺-releasing hydrogels. (a) Zn²⁺-releasing hydrogel scheme, digital images of the sol-gel phase transition. Phase transition time of hydrogel depending... 59

Fig. 2.2. Zn²⁺ and H₂O₂ releasing kinetics. (a) Zn²⁺ cumulative release profile, (b) release percent of feed amount depend on zinc peroxide concentration. (c) H₂O₂ cumulative release profile... 62

Fig. 2.3. Biocompatibility of the hydrogels. (a) Optical images and fluorescence microscopic images of HDFs cultured with hydrogels for 1 day (live cells in green; dead cells in red). (b) Cell... 64

Fig. 2.4. In vivo effect of anti-inflammatory macrophages to hydrogels. Representative immunofluorescence images and quantification analysis of macrophage in hydrogels on day 14... 67

Fig. 2.5. In vivo cell proliferation and angiogenic effect. Representative immunofluorescence images and quantification analysis of macrophage in hydrogels on day 14 after hydrogels... 69

Fig. 2.6. In vivo wound closing and collagen maturation. (a) Schematic representations of critical defect model (b) Representative digital images of wounds and (c) quantitative analysis of wound... 72