Detail View

Development of an Integrated Magnetic Actuation and Focused Ultrasound System for Efficient Targeted Drug Delivery
Citations

WEB OF SCIENCE

Citations

SCOPUS

Metadata Downloads

Title
Development of an Integrated Magnetic Actuation and Focused Ultrasound System for Efficient Targeted Drug Delivery
Alternative Title
효율적인 표적약물전달을 위한 자기장 구동 및 초음파 통합 시스템 개발
DGIST Authors
Hyeonwoo KeeSukho ParkEunjoo Kim
Advisor
박석호
Co-Advisor(s)
Eunjoo Kim
Issued Date
2026
Awarded Date
2026-02-01
Type
Thesis
Description
Brain cancer treatment, Magnetic drug delivery, Focused ultrasound, Electromagnetic actuation, Integrated system
Abstract

자기 약물 전달 또는 자기 약물 표적(Magnetic Drug Delivery/Magnetic Drug Targeting, MDD/MDT)은 약물을 질병 부위에 직접 전달하여 부작용을 줄이고 치료의 정확성을 높이는 표적 치료 방법이다. MDD/MDT는 특히 뇌종양 치료에 유망하지만, 혈뇌장벽(Blood-Brain Barrier, BBB)이 존재해 약물이 충분히 교모세포종(Glioblastoma Multiforme, GBM) 부위에 도달하지 못하는 경우가 많다. 최근 초음파를 이용한 BBB 개방 기법이 연구되어 치료제의 종양 접근성을 높였으나, BBB 개방과 MDD/MDT의 최적화를 통해 GBM에서 약물 전달을 향상시키는 것은 여전히 중요한 과제로 남아 있다. 본 연구는 BBB 개방과 MDD/MDT를 결합하여 GBM에서의 약물 전달 효율과 치료 효과를 개선하는 FUEM(Focused Ultrasound and Electromagnetic Actuation) 시스템이라는 통합 시스템을 제안한다. FUEM 시스템은 먼저 초음파(FUS)와 마이크로버블을 이용해 일시적이고 제어된 BBB 개방을 유도하여 약물이 BBB를 통과해 종양 부위에 도달할 수 있도록 한다. 그 후 전자석(Electromagnet, EM)을 이용하여 MNP(자성 나노입자)를 종양 부위로 정확히 유도하며, EM이 생성하는 동적 자기장을 통해 MNP의 응집을 방지하여 좁은 모세혈관과 일부 BBB가 유지된 부위를 원활히 통과하도록 한다. FUEM 시스템의 설계는 유한요소법(Finite Element Method, FEM) 시뮬레이션을 통해 개발되었고, 뇌종양 환경을 모사한 in vitro BBB 모델을 이용해 실험적으로 검증하였다. 결과는 FUEM이 종양 부위에서 MNP 축적을 크게 증가시키며, 비표적 부위로의 의도치 않은 약물 확산을 최소화한다는 것을 보여주었다. EM이 생성하는 동적 자기장은 MNP 체인 형성을 효과적으로 분해하여 좁은 공간에서도 효율적인 이동을 가능하게 했으며, 기존의 정적 영구자석(PM) 또는 EM 시스템보다 높은 약물 전달 효율을 달성하였다. FUEM 시스템은 BBB 개방과 정확한 MDD/MDT의 문제를 해결하여 GBM에서의 약물 표적 전달을 강화하는 강력한 솔루션을 제공한다. 따라서 FUEM 시스템은 GBM 치료의 현재 한계를 극복하기 위한 새로운 통합 접근법을 제시하며, BBB 통과와 MNP 응집 문제를 해결함으로써 더 나은 치료 결과를 위한 잠재적인 솔루션을 제공한다. 본 연구는 GBM에 국한되지 않고 다양한 암 치료에도 적용 가능한 초음파와 자기장 기반 약물 전달 시스템의 임상 적용 가능성을 탐구하는 기초를 마련하여, 암 치료 전반에 새로운 치료적 개입의 길을 제시한다.|Magnetic drug delivery—also referred to as magnetic drug targeting (MDD/MDT)—is a targeted therapeutic approach designed to deliver drugs directly to disease sites, reducing side effects and enhancing treatment precision. MDD/MDT shows significant promise for brain tumor treatment; however, the blood-brain barrier (BBB) often prevents adequate drug delivery to glioblastoma multiforme (GBM) tumors. While recent studies have explored using focused ultrasound (FUS) to transiently open the BBB and improve drug access to tumors, optimizing MDD/MDT in conjunction with BBB opening remains a critical challenge for enhancing drug delivery in GBM. This study proposes an integrated system, the Focused Ultrasound and Electromagnetic actuation (FUEM) system, to enhance drug delivery efficiency and therapeutic efficacy in GBM by combining BBB opening with MDD/MDT. The FUEM system initially employs FUS with microbubbles to achieve a temporary and controlled BBB opening, allowing drug-loaded magnetic nanoparticles (MNPs) to pass through the BBB and reach the tumor site. An electromagnet (EM) is then used for precise guidance of MNPs to the target site and generation of dynamic magnetic fields to prevent MNP aggregation and facilitate passage through narrow capillaries and partially disrupted BBB regions. The design of the FUEM system was developed through finite element method (FEM) simulations and experimentally validated using an in vitro BBB model that mimics brain tumor conditions. Results indicate that the FUEM system significantly enhances MNP accumulation at the tumor site while minimizing off-target drug dispersion by combining BBB opening and MDD/MDT. The dynamic magnetic field generated by the EM effectively disrupts MNP chain formation, enabling efficient navigation through constrained spaces and achieving superior drug delivery efficiency compared to conventional static permanent magnet (PM) or EM systems. The FUEM system offers a robust solution for overcoming the challenges associated with BBB opening and precise MDD/MDT, thereby improving drug targeting in GBM. Thus, the FUEM system presents a novel, integrated approach to addressing current limitations in GBM treatment by enabling both BBB passage and controlled MNP delivery. This study lays a foundation for the potential clinical application of FUS and magnetic actuation-based drug delivery systems not only for GBM but also for a broad range of cancer therapies, providing new avenues for advancing cancer treatment overall. Keywords: Brain cancer treatment, Magnetic drug delivery, Focused ultrasound, Electromagnetic actuation, Integrated system

더보기
Table Of Contents
Ⅰ. Introduction 1
1.1 Magnetic drug delivery 1
1.1.1 Conventional cancer therapy 1
1.1.2 Magnetic drug delivery 2
1.1.3 Conventional magnetic drug delivery 3
1.1.4 Limitation of conventional magnetic drug delivery 4
1.2 Electromagnetic actuation (EMA) system for magnetic drug delivery 4
1.3 Permanent magnet (PM) array for focused magnetic drug delivery 5
1.4 Blood-brain/tumor barrier (BBB) 6
1.4.1 Impact of presence of intact BBB on magnetic drug delivery 6
1.4.2 BBB opening using focused ultrasound (FUS) and microbubbles 7
1.5 Time-varying magnetic field for magnetic nanoparticles (MNPs) disassembly 8
1.5.1 MNPs as magnetic drug carrier in magnetic drug delivery 8
1.5.2 Aggregation of MNPs under static magnetic field 9
1.5.3 Disassembly of MNPs under time-varying dynamic magnetic field 9
1.6 Proposal 10
1.7 Dissertation overview 11
ⅠI. Investigation of EMA System Characteristics for MDD/MDT 12
2.1 Introduction 12
2.2 Design of the quadrupole EMA system with movable iron cores 14
2.2.1 Flow chart for magnetic drug carrier (MDC) actuation by the quadrupole EMA system 14
2.2.2 Concept and design of the quadrupole EMA system 16
2.2.3 Relationship between workspace and position of magnetic iron core 17
2.2.4 Theoretical background 18
2.2.5 Experimental setup 18
2.2.6 Verification of generated magnetic field 19
2.3 Analysis of the change of drivable area (DA) due to the change of core position 20
2.3.1 Definition and analysis of drivable area (DA) 20
2.3.2 DA estimation by finite element method (FEM) 23
2.3.3 DA measurement experiments 26
2.3.4 Verification test of DA by MDC manipulation 27
2.4 Analysis of the change of magnetic forces due to the change of core position 28
2.4.1 Reduction of energy dissipation due to the change of core position 28
2.4.2 Manipulation of MDCs of various sizes using the EMA system 31
2.5 Discussion 32
2.6 Conclusion 34
ⅠII. Investigation of PM Array Characteristics for MDD/MDT 35
3.1 Introduction 35
3.2 Design of the modified Halbach array for focused magnetic drug delivery 36
3.2.1 Focused magnetic drug targeting (FMDT) 37
3.2.2 Modified Halbach array design for FMDT 38
3.3 Optimization of the proposed FMDT 41
3.3.1 Theoretical background 41
3.3.2 Conditions for the finite element method (FEM) simulation 42
3.3.3 Optimization of magnetic force magnitude 45
3.3.4 Optimization of local focusing with wide attraction 46
3.4 Experimental validation 47
3.4.1 Experimental setup 48
3.4.2 Validation of effect of gap change 49
3.4.3 Validation of effect on the magnet type 50
3.5 Conclusion 52
ⅠV. Integrated Focused Ultrasound and Electromagnetic Actuation (FUEM) System for MDD/MDT to brain cancer 53
4.1 Introduction 53
4.2 Results and discussion 56
4.2.1 blood-brain barrier (BBB) Opening 57
4.2.1.1 Design and validation of FUS unit 57
4.2.1.2 Blood-brain barrier (BBB) opening test using FUS and microbubbles 58
4.2.2 Magnetic nanoparticles penetration test for MDT 60
4.2.2.1 Design and validation of electromagnetic actuation (EMA) unit 60
4.2.2.2 MNP penetration test 63
4.2.3 Therapeutic efficacy evaluation 66
4.2.3.1 Preparation of drug-loaded MNPs 66
4.2.3.2 In vitro therapeutic efficacy test 67
4.3 Materials and methods 70
4.3.1 Materials 70
4.3.2 Simulation and Validation Methods for Focused Ultrasound (FUS) Unit 70
4.3.3 Fabrication of In Vitro Blood-Brain Barrier (BBB) Model 71
4.3.4 BBB Opening Test in In vitro BBB model using MBs and FUS unit 72
4.3.5 Simulation and validation methods for EMA unit 73
4.3.6 Magnetic Nanoparticle (MNP) Penetration Test in In vitro BBB model 74
4.3.7 DOX Loading on MNPs 76
4.3.8 DOX Release of DOX-loaded MNPs 77
4.3.9 In Vitro Cytotoxicity Test 78
4.3.10 In vitro Therapeutic Efficacy Evaluation 78
4.3.11 Statistical Analysis 79
4.4 Conclusion 79
V. Conclusion and Future Works 81
5.1 Summary and discussion 81
5.2 Improvement for conventional MDT to brain cancer 82
5.3 Expansion to In Vivo Studies 84
5.4 Future works 85
5.4.1 Integration of the Modified Halbach Array into the FUEM System for In Vivo Studies 85
5.4.2 On-Demand Drug Release Using Magneto-Electric Nanoparticles 86
5.4.3 Optimization of magnetic field generated by EMA system 87
References 89
Appendix A 100
Appendix B 106
요약문 116
URI
https://scholar.dgist.ac.kr/handle/20.500.11750/59607
http://dgist.dcollection.net/common/orgView/200000949851
DOI
10.22677/THESIS.200000949851
Degree
Doctor
Department
Department of Robotics and Mechatronics Engineering
Publisher
DGIST
Show Full Item Record

File Downloads

  • There are no files associated with this item.

공유

qrcode
공유하기

Total Views & Downloads