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국회도서관 홈으로 정보검색 소장정보 검색

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동의어 포함

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Title Page 2

Contents 5

Abstract 13

Chapter 1. Introduction 15

1.1. Point-of-care testing Technology (POCT) 15

1.2. POCT Device Architecture and Integration 19

1.2.1. Lab-on-a-chip Systems 19

1.2.2. Microfluidics-based POCT 19

1.2.3. Integrated POC Cartridges 21

1.3. Detection Techniques in POCT Devices 24

1.3.1. Electrochemical Sensing 24

1.3.2. Colorimetric Assays 24

1.3.3. Chemiluminescence Assays 24

1.3.4. Fluorescence-Based Detection 25

1.3.5. Digital fluorescence-based POCT 25

1.4. Detection Modalities in POCT: Direct and Indirect health monitoring 28

1.4.1. Direct health monitoring 28

1.4.2. Indirect health monitoring 28

1.5. Immunoassay and its integration in POCT 31

1.5.1. Direct immunoassay 31

1.5.2. Indirect immunoassay 31

1.5.3. Competitive immunoassay 31

1.5.4. Sandwich immunoassay 32

1.6. Integration of nanoparticles in POCT 32

1.6.1. Properties and benefits of NPs in POCT 33

1.6.2. Fluorescence-based NPs in POCT 34

1.6.3. Magnetic NPs in POCT 34

1.7. Literature review 35

1.7.1. Use of POCT in indirect health monitoring 35

1.7.2. Use of POCT in direct health monitoring 36

1.8. Shortcomings of current platforms 39

1.9. Overview of the thesis 41

Chapter 2. Culture-Free Quantification of Bacteria Using Digital Fluorescence Imaging in a Tunable Magnetic Capturing Cartridge for Onsite Food Testing 43

Abstract 43

2.1. Introduction 45

2.2. Experimental Section 50

2.2.1. Chemical and Sample Preparation 50

2.2.2. Sample preparation for imaging and counting 50

2.2.3. Materials, design, and fabrication of the TMCC 52

2.2.4. Digital fluorescence imaging system hardware and software 53

2.3. Results and Discussion 54

2.3.1. Design of the TMCC and bacterial detection strategy 54

2.3.2. Control of capture time in the TMCC 58

2.3.3. Design and fabrication of an automated, highly portable fluorescence reader 67

2.3.4. Statistical evaluation and accuracy of the developed system 70

2.3.5. Operational efficiency of bacterial detection from real food samples 76

2.4. Summary 79

Chapter 3. A self-driven microfluidic immunoassay cartridge with magnetic nanoparticles for high-precision fluorescence-based quantification 81

Abstract 81

3.1. Introduction 82

3.2. Experimental Section 86

3.2.1. Chemical and reagents 86

3.2.2. Probe modifications 86

3.2.3. GFM treatment for loading of Abs 87

3.2.4. Fabrication of SDMIC 88

3.2.5. Dimensions of the SDMIC 92

3.2.6. Digital imaging and post-processing 92

3.2.7. COMSOL simulation 92

3.2.8. Machine Learning 93

3.3. Results and Discussion 95

3.3.1. Design and working principle of SDMIC 95

3.3.2. Concept of washing and bubble trapping on SDMIC 98

3.3.3. Fabrication of SDMIC 103

3.3.4. Characterization of flow time, release of MNPs, and capturing efficiency in the cartridge 106

3.3.5. Proof of concept of off-the-cartridge measurements 111

3.3.6. Optimization and quantification of different CRP concentrations in the cartridge 118

3.3.7. Integration of Machine Learning into the SDMIC platform 124

3.4. Summary 130

Chapter 4. Conclusion and Future Perspectives 131

References 134

논문요약 175

List of Tables 9

Table 2.1. Comparison of the current work (TMCC) with previously published works 49

Table 2.2. Comparison between the plate count method and the proposed integrated detection... 56

Table 2.3. Absorption pads loaded with 60 µL of LMPVA solution at different concentrations... 62

Table 2.4. Absorption pads coated with 40 µL of LMPVA solutions at 29 and 30wt.% and the... 62

Table 2.5. Capture efficiency of bacteria in the TMCC assembled with an absorption pad... 63

Table 2.6. Capture efficiency of bacteria bound with 100-nm MNPs conjugated with Abs in a... 63

Table 2.7. TMCC count vs. plate count with an absorption pad impregnated with 30wt.% LMPVA... 72

Table 3.1. Regression hyperparameters and evaluation matrices of different models 127

Table 3.2. Multi-classification hyperparameters and evaluation matrices for different models 128

Table 3.3. Comparison of coefficient of determination (R²) from different ML models 129

List of Figures 10

Figure 1.1. Schematic illustration of traditional vs. POCT device for disease detection. Traditional... 18

Figure 1.2. Demonstration of "ASSURED" criteria of POCT 18

Figure 1.3. Demonstrate the types of Lab-on-a-Chip (LoC) technology. LoC platform can be... 23

Figure 1.4. Detection techniques in POCT. POCT can employ electrochemical, colorimetric,... 27

Figure 1.5. Detection modalities of POCT. POCT can be utilized in direct health monitoring for... 30

Figure 1.6. Types of POCT devices in direct and indirect health monitoring. (a) A smartphone-... 38

Figure 2.1. Schematic representation of the TMCC design, bacterial capture, and quantification... 57

Figure 2.2. Optimization of the concentration and volume of PVA solutions for barrier formation... 64

Figure 2.3. Microscopic image of the absorption pad: PVA-coated region (left) and bare region... 65

Figure 2.4. Photographs of non-uniform PVA impregnation in the absorption pad with 30wt.%... 65

Figure 2.5. Capture efficiency of the TMCC assembled with an absorption pad impregnated with... 66

Figure 2.6. Comparison of the capture efficiency of magnetic nanoparticles (MNPs) with... 66

Figure 2.7. Design of the por Table digital fluorescence imaging system and the bacterial counting... 69

Figure 2.8. Statistical evaluation of the working performance of the developed TMCC and... 74

Figure 2.9. Fluorescence and optical images of S. aureus cells captured on the TMCC and an agar... 75

Figure 2.10. Determination of the accuracy of the fully integrated system for bacterial... 78

Figure 2.11. Comparison between the plate count after concentration and separation of S. aureus... 78

Figure 3.1. Illustration of the fabrication procedure for the cartridge. The 3D design of molds was... 90

Figure 3.2. Illustration of the chemical bonding procedure for the PDMS replica. The top layer... 91

Figure 3.3. The dimension of the SDMIC. (a) Dimension of different compartments of the... 94

Figure 3.4. Schematic illustration of the "SDMIC" components, design, and working protocol.... 97

Figure 3.5. Concept of washing, trapping of bubbles, and capturing of MNPs in the SDMIC. (a)... 101

Figure 3.6. Simulation of magnetic field lines and strength of 1x1 mm magnet in the sensing... 102

Figure 3.7. Contact angle of PDMS and PDMS-b-PEO. (a) Photograph of water drops on PDMS... 105

Figure 3.8. Characterization of flow time, release of MNPs, and capturing efficiency in the... 110

Figure 3.9. Concept of immunocomplex formation, detection protocol, and optimization of... 115

Figure 3.10. Absorbance of MNPs and effect of different excitation wavelength of QDs. (a)... 116

Figure 3.11. Effect of BSA addition in PBS solution before CRP dilution. (a) Digital fluorescence... 116

Figure 3.12. Absorbance of different amounts of MNPs at different wavelengths 117

Figure 3.13. Off-the-cartridge immunoassay with different concentrations of CRP. Digital... 117

Figure 3.14. Visualization and testing of CRP immunocomplex formation with varying CRP... 122

Figure 3.15. DP probe optimization on the SDMIC. Fluorescence images of immunocomplex of... 123

Figure 3.16. Digital fluorescence image of immunocomplex of different concentrations of CRP... 123

Figure 3.17. Workflow concept of machine learning models in regression and multiclassification... 126

초록보기

 개인 맞춤형 의료 및 신속 진단에 대한 수요가 계속 증가함에 따라, 실시간 현장 분석이 가능한 통합 현장 현시 검사(POCT) 플랫폼의 개발이 점점 더 중요해지고 있습니다. 본 논문은 간접 및 직접 건강 모니터링을 위한 두 가지 첨단 POCT 시스템의 설계 및 구현에 초점을 맞추고 있으며, 현장 배치 가능 진단과 관련된 주요 과제를 해결합니다.

식품 매트릭스 내 병원균 검출을 포함하는 간접 건강 모니터링을 위해, 시간이 많이 소요되는 농축 단계 없이 대용량 식품 샘플에서 황색포도상구균을 신속하고 정량적으로 검출하기 위한 가변 자기 포획 카트리지(TMCC)가 개발되었습니다. 자기영동 농축법은 대용량 샘플을 처리하는 데 사용되었으며, 유전영동 기반 분리 장치는 결합되지 않은 프로브와 식품 입자를 제거하여 검출 정확도를 향상시키는 데 활용되었습니다. TMCC는 맞춤형 휴대용 형광 판독기를 사용하여 정량 분석을 위한 효율적인 박테리아 포획 및 이미징을 가능하게 했습니다. 높은 특이도와 민감도를 보장하기 위해 샌드위치 면역분석법 형식이 사용되었습니다. 이 플랫폼은 표준 방법과 비교하여 우수한 성능을 보여주었습니다.

직접 건강 모니터링을 위해, 소형의 모세관 유동 기반 설계를 사용하여 완전히 통합된 펌프 없는 바이오마커 검출을 가능하게 하는 자가 구동 미세유체 면역분석 카트리지가 개발되었습니다. 면역분석에 필요한 모든 시약은 카트리지에 미리 탑재되어 외부 장비 없이 시료 주입부터 결과 분석까지의 작동을 가능하게 합니다. 자기 나노입자는 이동 가능한 기질로 사용되었고, 양자점은 민감도와 신호 증폭을 향상시키기 위한 형광 태그로 사용되었습니다. 결합되지 않은 프로브를 제거하여 표적 정량화의 정밀도를 향상시키기 위해 전용 세척 구역이 통합되었으며, 프로브 로딩을 위한 유리 섬유 멤브레인의 사용은 제작을 단순화하고 분석 재현성을 보장했습니다.

불충분한 민감도, 외부 구동 장치 요구사항, 시약 불안정성 및 매트릭스 간섭과 같은 현재 POCT 시스템의 주요 한계를 해결함으로써, 본 연구는 임상 진단 및 식품 안전 모니터링 모두를 위한 견고하고 현장 적용 가능한 솔루션을 제시합니다. 본 연구에서 개발된 통합 플랫폼은 휴대 가능하고 저렴하며 매우 정확한 POCT 시스템을 구현하는 데 있어 중요한 진전을 나타내며, 예방적 의료 및 실시간 모니터링 분야에서의 광범위한 배치를 위한 새로운 가능성을 엽니다.