Title Page

Contents

Abstract 21

Chapter 1. Introduction 23

1.1. Energy harvesting technology/energy harvesters 23

1.2. Triboelectric nanogenerators (TENGs) 25

1.3. Implantable TENGs for healthcare 33

1.4. Ultrasound-driven implanted TENG 37

1.5. Biocompatible and biodegradable TENG 40

1.6. Sub-tissue non-drug antibacterial technologies 43

1.7. Electrical stimulation for bacteria inactivation 47

Chapter 2. Ultrasound-driven on-demand transient triboelectric nanogenerator for subcutaneous antibacterial activity 50

2.1. Abstract 50

2.2. Introduction 51

2.3. Results and discussion 54

2.3.1. The design, materials, and output performance of IBV-TENG 54

2.3.2. Characterizing biodegradation rate of materials composing the IBV-TENG 68

2.3.3. In vitro evaluation and mechanism of the antibacterial effect of IBV-TENG 71

2.3.4. Antibacterial effect of ultrasound inducing and pH measurement after applying electrical stimulation 75

2.3.5. Experimental setup of ex vivo test and evaluating the output performance of implanted IBV-TENG inside porcine tissue under ultrasound 78

2.3.6. Ex vivo test for evaluating the antibacterial ability of IBV-TENG 80

2.4. Experimental Section 82

2.4.1. Fabrication of biodegradable films 82

2.4.2. Manufacturing of IBV-TENG 82

2.4.3. Characterizing degradation time of the materials 83

2.4.4. Biocompatibility test (MTT assay) 84

2.4.5. Measurement of output performance of IBV-TENG 84

2.4.6. Bacteria cultures process 85

2.4.7. In vitro antibacterial test 86

2.4.8. Ex vivo antibacterial test 87

2.4.9. Statistical analysis 88

2.5. Conclusion 89

Chapter 3. Sub-tissue electrostatic antimicrobial by transient ultrasound-based triboelectric generator 90

3.1. Abstract 90

3.2. Introduction 91

3.3. Results and discussion 93

3.3.1. Design and materials of MI-TENG 93

3.3.2. Characterizing the materials composing the MI-TENG 99

3.3.3. Characterizing biodegradation and biocompatibilty of materials 106

3.3.4. Characterizing biodegradation and biocompatibilty of materials 110

3.4. Experimental Section 114

3.4.1. Fabrication of biodegradable films 114

3.4.2. Manufacturing of MI-TENG 114

3.4.3. Characterizing degradation time of the materials 115

3.4.4. Biocompatibility test (MTT assay) 115

3.4.5. Measurement of output performance of IBV-TENG 116

3.4.6. Bacteria cultures process 117

3.4.7. In vivo antibacterial test 118

3.4.8. Statistical analysis 118

3.5. Conclusion 120

Chapter 4. Summary and outlook 121

References 123

Chapter 1. Introduction 123

Chapter 2. Ultrasound-driven on-demand transient triboelectric nanogenerator for subcutaneous antibacterial activity 130

Chapter 3. Sub-tissue electrostatic antimicrobial by transient ultrasound-based triboelectric generator 134

Appendix 139

논문요약 141

Chapter 1. Introduction 9

Figure 1.1. Development of wireless technology in harvesting or transmitting energy from the ambient environment. Reproduced with permission. Copyright... 24

Figure 1.2. Fundamental modes of triboelectric nanogenerators: (a) Contact-separation mode, (b) Lateral sliding mode, (c) Single electrode mode and (d)... 30

Figure 1.3. Contact electrification (CE) or triboelectrification mechanism of mechanical energy to electrical power during contact or friction process. (a)... 31

Figure 1.4. (a) A summary of the four major application fields of TENGs as micro/nano power sources, active self-powered sensors, blueenergy, and... 32

Figure 1.5. Implantable measurement devices for biomedical applications 35

Figure 1.6. Overview of the implantable biomedical devices based on triboelectric nanogenerators (TENGs) incorporating self-powered biosensors,... 36

Figure 1.7. US-driven implantable TENG as an energy harvesting system for biomedical applications. Reproduced with permission. Copyright 2022, Elsevier 38

Figure 1.8. Powering implantable medical devices (IMDs) with piezoelectricity/triboelectricity generated from different mechanical energy sources 39

Figure 1.9. Biocompatible and biodegradable implanted TENG-based devices used in medical applications 42

Figure 1.10. An overview of non-drug antibacterial methods: (A) Thermo-responsive triple-function nanotransporter for efficient chemo-PTT of... 46

Figure 1.11. (A) Diagram showing antibacterial mechanism on the antibacterial platform based on capacitive carbon-doped TiO₂ nanotubes after inducing... 49

Chapter 2. Ultrasound-driven on-demand transient triboelectric nanogenerator for subcutaneous antibacterial activity 11

Figure 2.1. Design and output performance of IBV-TENG. A) Schematic illustration of IBV-TENG based on US under the surgical site to prevent SSI by... 56

Figure 2.2. The surface potential of PHBV and PVA films measured by Kelvin probe force microscopy (KPFM). These are the surface potentials of PHBV and... 58

Figure 2.3. Chemical structure and FTIR spectroscopy spectra to identify the synthesized polymers (PHBV, PVA) 59

Figure 2.4. The manufacturing process of IBV-TENG device. A) Initially, PHBV solution (5%, w/v) was spin-coated on the Mg electrode (dimension of 1 × 2... 60

Figure 2.5. Experimental setup of equipment for checking the output of IBV-TENG under ultrasound probe in water. A) The output voltage signal of the IBV-... 62

Figure 2.6. The output voltage signal of IBV-TENG under different ultrasound intensities. The output voltage of IBV-TENG under the different ultrasound... 63

Figure 2.7. The output voltage signal of IBV-TENG under different ultrasound probe distances. The output voltage of IBV-TENG devices under different... 64

Figure 2.8. Charge generation of IBV-TENG under ultrasound. As shown, the phenomena of the charge generation mechanism of IBV-TENG by inducing... 65

Figure 2.9. Experimental setup for checking the output of IBV-TENG when using PDMS and ultrasonic gel as a matching layer. A) Schematic diagram and B) real... 67

Figure 2.10. Characterizing biodegradation rate of materials composing the IBV-TENG. A) Photograph of biodegradation level for every 2 weeks and B) the... 70

Figure 2.11. In vitro evaluation of the antibacterial effect of IBV-TENG by making ES. A) Schematic of the experimental setup evaluating the antibacterial... 73

Figure 2.12. Measurement of antibacterial effect of direct ultrasound inducing. A) Schematic diagram and Real image of experiment setup for checking the... 76

Figure 2.13. Experimental setup of ex vivo test. A) evaluating the output performance and the antibacterial effect of implanted IBV-TENG inside porcine... 79

Figure 2.14. Ex vivo test process for evaluating the antibacterial ability of IBV-TENG device by making electrical stimulation under ultrasound. A) respectively,... 81

Chapter 3. Sub-tissue electrostatic antimicrobial by transient ultrasound-based triboelectric generator 17

Figure 3.1. a) schematic illustration of ultrasound-driven MI-TENG after and before implanting under the surgical site, b) photograph and size of MI-TENG.... 95

Figure 3.2. Chemical structure and FTIR spectroscopy spectra to identify the synthesized polymers (PHBV, PEVA) 96

Figure 3.3. The schematic illustration of fabricating steps of MI-TENG. a) a Mg plate (20 μm thickness, 1 × 2 cm²) was PEVA-coated (5 μm thickness) by... 97

Figure 3.4. a) and b) SEM images results of surfce and creoss-section viewe of the PHBV and Mg powder composite 102

Figure 3.5. EDS results for PHBV and MgP-PHBV composites 103

Figure 3.6. a) and b) photograph and diagram of contact angle results of materials composing the MI-TENG (PHBV, PEVA, Mg, MgP-PHBV) 104

Figure 3.7. The surface potential of PHBV and Mg composites films measured by Kelvin probe force microscopy (KPFM). These surface potentials were measured... 105

Figure 3.8. a-c) Photograph of biodegradation rate of Mg, PHBV, and MgP-PHBV in PBS (pH 7.4, 37 ℃). The thickness of Mg foil, PHBV, and MgP-PHBV films...[이미지참조] 107

Figure 3.9. Biocompatibility testing (MTT assay) of PHBV, PEVA, and MgP-PHBV 108

Figure 3.10. The image of bacteria colony of E. coli for antibacteria checking of the materials composing the MI-TENG (Mg, PHBV, PEVA, and MgP-PHBV)[이미지참조] 109

Figure 3.11. The output voltage signal of device with different tribo friction layers (PHBV/Mg, PHBV/PEVA, and PHBV/F-PEVA). The ultrasound probe was... 111

Figure 3.12. The output voltage signal of device with different tribo friction layers (MgP-PHBV/F-PEVA and MgP-PHBV/F-PEVA). The ultrasound probe was... 112

Figure 3.13. In vivo test for evaluating the sub-tissue antibacterial ability of MI-TENG ES under US. A) respectively, (i) 10 μL of bacteria solution (~105...[이미지참조] 113

Appendix 20

Figure A. Biodegradable TENG based on the ϰC-Agar composite. (a) Schematic structure, (b) working principle, (c) a photograph of the biodegradable TENG... 140