| Author: | Huang, Yingying |
| Title: | Functionalized nanomaterials for T cell monitoring and immunotherapy |
| Advisors: | Yang, Mo (BME) Wong, Siu-hong Dexter (BME) |
| Degree: | Ph.D. |
| Year: | 2025 |
| Department: | Department of Biomedical Engineering |
| Pages: | xxvii, 135 pages : color illustrations |
| Language: | English |
| Abstract: | T lymphocytes, particularly their antigen-directed cytotoxicity, are pivotal in harnessing the immune system against cancer. Despite advancements in T cell sensing and immunotherapy, current methods often face efficacy limitations and side effects. In recent years, functionalized nanomaterials have garnered significant attention in biosensing and disease treatment. In this thesis, we developed a novel aggregation-induced emission fluorophore (AIEgen) based nanoprobe capable of targeting mouse CD8+ T cells. This nanoprobe can sensitively and selectively distinguish T cells in different differentiation states based on differences in intracellular pH (pHi) generated by metabolic differences. Furthermore, inspired by the crucial role of mature T lymphocytes in cancer therapy, we fabricated aptamer-functionalized methylgermane nanosheet (mGeNS) probes to detect BRCA1, a gene implicated in T-cell immune function. Moreover, leveraging the exceptional photothermal performance of mGeNS, we engineered a mGeNS-based hydrogel platform with near-infrared (NIR) light-controlled drug release kinetics, enabling mGeNS to maintain effective concentrations and a stable photothermal effect at local tumor lesion sites. In the first work, we aimed to enable non-invasive monitoring of T cell activation and differentiation states by leveraging distinct cellular metabolic pathways (e.g., glycolysis), which are hypothesized to correlate with different pHi levels. To achieve this, we designed a novel dual emission enhancement nanoplatform composed of AIE dyes, AIEgen@F127-AptCD8, which enables accurate detection of pHi in T cells to "read" the T cell differentiation process. The nanoprobe exhibits a broadly responsive range for pHi values (9.0 to 4.0) and a highly sensitive narrow range for pHi values (7.4 to 6.0), facilitating non-invasive and reliable pHi detection in different cell states. This work demonstrates the specificity and dynamic detection capabilities of this nanoprobe for indirectly and non-invasively monitoring T cell activation and differentiation states. In the second work, we developed a new biosensor (GeT-NSs@FAM-cDNA) based on a mGe-nanosheet/aptamer platform for the mutant BRCA1 gene detection. This platform utilizes mGe-nanosheet as a fluorescence quencher, which has been rarely studied in biosensor detection. Compared to traditional fluorescence quenchers such as graphene and MoS₂, mGeNS offers a wide absorption wavelength from the ultraviolet to the NIR region and excellent fluorescence emission at 640 nm. When bound to an organic small molecule fluorescent aptamer (FAM-cDNA), the fluorescence of oligonucleotides is quenched by the mGe-nanosheet due to Van der Waals forces, resulting in a fluorescence "off" state. Upon the addition of the target DNA, the BRCA1 mutant sequence, the fluorescence is restored ("on" state), enabling detection through ratiometric fluorescence emission signals (I520/I640 nm). The platform exhibited high selectivity and sensitivity, which was confirmed using mismatched ssDNA and microRNA sequences. This work demonstrates that GeT-NSs@FAM-cDNA nanoprobes can identify the mutant BRCA1 gene with rapid detection (< 30 min) and good sensitivity at the picomolar level without amplification. In the third study, we focused on delaying the degradation kinetics of mGeNS and enhancing their photothermal stability for tumor therapy. To achieve this, we developed a composite mGeNS-based hydrogel formulation, termed AIMR, which was constructed by encapsulating polyvinylpyrrolidone-modified and doxorubicin-loaded mGeNS (DOX-mGeNS@PVP) into Ca²⁺-cross-linked sodium alginate hydrogel. Under near-infrared light (NIR) irradiation, the embedded mGeNS@PVP exhibits an excellent photothermal effect with a photothermal conversion efficiency of 60.6%, promoting AIMR degradation and releasing immunomodulatory substances (DOX-mGeNS@PVP and Ca²⁺ ion). This process triggered endoplasmic reticulum (ER) stress and mitochondrial dysfunction, and accelerates the generation of immune-related biomarkers, thereby synergistically amplifying the immunogenic cycle. Furthermore, the AIMR enhances anti-tumor immunity by increasing CD4+/CD8+ T cell infiltration, reducing regulatory T cells, and increasing inflammatory cytokine secretion. Notably, the amplified immunogenic cycle achieves an abscopal effect, effectively inhibiting the growth of distant untreated tumors. This work highlights the potential of smart photothermal agents in hydrogel-based "all-in-one" immunotherapy and inspires the application of mGeNS-based therapeutic hydrogel platforms in postoperative cancer treatment and personalized biomedicine. |
| Rights: | All rights reserved |
| Access: | open access |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/14511