| Author: | Zhang, Ruolin |
| Title: | Nanomaterial-based exosome detection and engineered exosome-nanomaterial complex for combinatorial cancer immunotherapy |
| Advisors: | Yang, Mo (BME) Tan, Youhua (BME) |
| Degree: | Ph.D. |
| Year: | 2023 |
| Subject: | Breast -- Cancer -- Molecular diagnosis Breast -- Cancer -- Molecular aspects Breast -- Cancer -- Prognosis Tumor markers Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Biomedical Engineering |
| Pages: | xxiv, 139 pages : color illustrations |
| Language: | English |
| Abstract: | Cancer is recognized as one of the most malignant and pernicious diseases which corresponds to its very aggressive and metastatic properties. Despite enormous efforts that have been dedicated to undercover more precisions detection and therapeutic methods, some patients were compromised by metastatic lesions at the initial diagnosis and damage to functional organisms of the side effect of conventional therapy ways such as chemotherapy. Thus, a highly sensitive approach to early cancer prognosis and targeted therapeutic methods are desperately needed for addressing precision medicine strategies regardless of the complex cancer heterogeneity. Exosome was considered the ideal bioinformatical marked carrier for early detection of cancer metastasis, clinical diagnosis, and therapy method suggesting. Taking the benefit of its high parent cell-like characteristics, and small scaled dimension, makes it became the practical nanocarrier for targeted cancer therapy and nanoparticle for cancer detection. Leveraging the current exosome detection methods such as Surface-Enhanced Raman Scattering (SERS), electrochemical, and ELASA, these approaches can achieve moderate detection efficiency. However, the detection efficiency limited the diagnosis accuracy and multi-cancer types of detection abilities. In the past decades, nanomaterials have illustrated the great potential for biomarker detection and therapy in nano-unit resolution for exosome study. Specifically, due to their superior optical properties, numerous nanomaterials worked as optical biosensors for exosome detection with high sensitivity and specificity. Moreover, although distinct properties of small size, great biocompatibility, targeting capacity, and the ability to overcome the biological barrier, natural exosomes have been widely used for various applications. However, there are still several limitations to establishing a biomedical application platform. Therefore, it is essential to develop the engineered exosomes as nanocarriers and encapsulated function molecules inside for delivering the therapeutic agents to the target area with high loading efficiency. Numerous nanomaterials could work as various therapeutic agents for cancer therapy such as photothermal therapy, photodynamic therapy, immunotherapy, etc. Thus, once the exosomes as nanocarriers with therapeutic nanomaterials are loaded, the engineered exosome complex could accomplish various cancer therapy with high targeting specificity and therapy efficiency. According to previous reports, breast cancer is one of the common malignant tumors and numerous approaches have been applied to diagnose breast cancer. The protein expression is the crucial factor to classify the cancer subtype. Therefore, the diagnosis and analysis of breast cancer could be accomplished according to the protein expression level. In this thesis, we first developed the aptasensor based on MoS2 nanosheets for simultaneous analysis and detection of breast cancer exosomes. Then the optimal engineered exosome preparation method was explored. Finally, I developed the M1-type macrophages derived exosomes-Mxene QDs (M1-Exo@Mxene QDs) for combinatorial photothermal and immunotherapy. In summary, nanomaterial-based exosome detection and engineered exosome-nanomaterial complex were developed and achieve the early diagnosis, detection, and therapy of breast cancer. In this thesis, we employ the molybdenum disulfide (MoS2) monolayer nanosheets for simultaneous analysis and detection of breast cancer exosomes. Due to its typical optical properties, we adopt the Fluorescence Resonance Energy Transfer (FRET) based aptasensor using MoS2 as quenching material. Her2, MUC1, and EpCAM are highly and abnormally expressed in breast cancer, which were chosen as tumor markers for analysis. The fluorescence modifiers such as Cy3, FAM, and Cy5 were selected to conjugate with MUCI, EpCAM, and Her2 aptamer, respectively. More specifically, the fluorescence signals will be quenched when incubating aptamer and MoS2 nanosheets, then the fluorescence recovery when interacting with specific proteins on the exosome surface. Further, to enhance the sensitivity of detection, DNase I was added to the reaction system to increase the detection efficiency and sensitivity. Detailly, while the formation of aptamer-exosome nanocomplex, DNase I separate the apatermers and results in exosome release to enlarge the fluorescence signal. In this study, three tumor markers on the surface of exosomes from different breast cancer exosomes (MCF-7, SK-BR-3, MDA-MB-231) were simultaneously analyzed via fluorescence signal. After achieving the high exosome detection sensitivity, we further developed engineered macrophage-derived exosomes coated with Mxene Quantum Dots (Mxene QDs) nanoparticles, termed M1-Exo@Mxene QDs for combinatorial cancer therapy. Taking the advantage of exosome’s cancer-targeting properties and natural biological similarities of the cells to cross the immune barriers. Besides, Mxene QDs, termed Ti3C2 QDs were synthesized and adopted to form the complex, due to their excellent photothermal effect under near-infrared (NIR) laser radiation. Apart from the PTT-caused cancer therapy effect, photothermal ablation can also induce immunogenic cell death (ICD). Specifically, the dead cancer cells can generate damage-associated molecular patterns (DAMPs), which could further induce the maturation of dendritic cells (DCs) and elicit the activation of T cells, finally resulting in the improvement of anti-tumor immunogenicity. Besides, M1 exosomes repolarize M2 tumor-associated macrophages (TAMs) to M1 macrophages to release pro-inflammatory cytokines and induce antitumor immune responses for cancer immunotherapy. Such combinatorial photothermal and immunotherapy enables cancer therapy could achieve highly anti-tumor efficiency in vitro and in vivo. |
| Rights: | All rights reserved |
| Access: | open access |
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