| 摘要: | 光治療（Photodynamic Therapy, PDT）作為一種新型的治療方式，由於其具有高選擇性和低毒性而受到廣泛關注。然而，現有的光敏劑，如靛氰綠（Indocyanine Green, ICG），在體內的不穩定性，限制了其應用。此外，研究表示微生物如大腸桿菌（E. coli）的成分能激發免疫系統，進一步增強抗癌效果，但其直接應用也面臨生物安全性問題。因此，將ICG和大腸桿菌裂解粉末包覆於聚乳酸-聚甘醇酸（PLGA）奈米粒子中，不僅能提高ICG的穩定性和標靶性，還能利用大腸桿菌裂解粉末的免疫活性作用，提供光免疫治療方法，使免疫細胞將PDT治療後的腫瘤進行近一步清除。本研究旨在研制包覆靛氰綠（Indocyanine Green, ICG）及大腸桿菌裂解粉末（E. coli）的聚乳酸-聚甘醇酸（PLGA）奈米粒子(ICG-E. coli-PLGA Nanoparticles ; IEPNPs)，應用於大腸癌的光免疫治療。
本研究結果中，IEPNPs的粒徑大小及表面電位分別為255.9 ± 22.7 nm和-25.8 ± 6.2 mV。藥物大腸桿菌裂解粉末和ICG包覆率分別為30 ± 0.1 %和85 ± 0.1 %。經由進紅外光照射IEPNPs中產生單態氧以及熱療效應中，IEPNPs檢測到的螢光值與相同濃度下ICG螢光值有顯著差異，為對照組的3倍。IEPNPs光治療升溫之效能數據表示IEPNPs在近紅外照射下會產生光熱效應造成IEPNPs中ICG含量80 µM在照射300秒中從25.5 ℃達到63.5 ℃，而相同濃度純ICG水溶液組中照射紅外光150秒鐘可從24.4 ℃達到85.4 ℃，結果顯示IEPNPs具有光熱治療效果。體外細胞毒性試驗結果可見，IEPNPs (ICG = 80 µM)存活率僅剩5 %，有顯著的毒性效果。
根據以上實驗評估IEPNPs能作為光免疫治療方法，不僅提升ICG的穩定性和標靶性，還能利用大腸桿菌裂解粉末的免疫活化作用，提供更為有效和安全的癌症治療方法，此技術將為大腸癌患者帶來新的治療選擇。
;Photodynamic therapy (PDT), as a novel treatment approach, has gained widespread attention due to its high selectivity and low toxicity. However, existing photosensitizers, such as indocyanine green (ICG), suffer from poor in vivo stability, limiting their clinical application. Additionally, studies have shown that components derived from microorganisms like Escherichia coli (E. coli) can stimulate the immune system and enhance anti-cancer effects. However, the direct use of such microbial components raises biosafety concerns. To address these issues, ICG and E. coli lysate powder (ECLP) were encapsulated into poly(lactic-co-glycolic acid) (PLGA) nanoparticles. This strategy improves the stability and targeting capability of ICG while utilizing the immune-stimulating effects of the ECLP. It provides a platform for photodynamic immunotherapy, enabling immune cells to further eliminate residual tumor cells after PDT treatment. This study aimed to develop PLGA nanoparticles encapsulating ICG and ECLP (ICG-E. coli-PLGA Nanoparticles; IEPNPs) for photodynamic immunotherapy of colorectal cancer.
The results showed that the average particle size and surface zeta potential of IEPNPs were 255.9 ± 22.7 nm and –25.8 ± 6.2 mV, respectively. The encapsulation efficiencies of ECLP and ICG were 30 ± 0.1% and 85 ± 0.1%, respectively. Upon near-infrared (NIR) irradiation, IEPNPs generated singlet oxygen and exhibited photothermal effects. The fluorescence intensity of IEPNPs was three times higher than that of free ICG at the same concentration. Photothermal analysis demonstrated that IEPNPs (ICG = 80 µM) increased in temperature from 25.5 °C to 63.5 °C after 300 seconds of NIR irradiation, whereas free ICG solution at the same concentration rose from 24.4 °C to 85.4 °C in just 150 seconds, confirming the photothermal effect of IEPNPs. In vitro cytotoxicity assays revealed that IEPNPs (ICG = 80 µM) reduced cell viability to only 5%, indicating significant cytotoxic effects. |
