高效双光子激发纳米光敏体系与肿瘤细胞光动力杀伤行为

Two-photon photodynamic therapy(TPPDT) has two important advantages including deep tissue penetration and exact localization. Therefore, TPPDT is promising to treat deep tumor tissue that is hard to be cured by general photodynamic therapy. However,TPPDT has several issues that need to be addressed, such as the low production efficiency of singlet oxygen of photosensitizer, poor tumor target of photosensitizer and the need of fast escape of photosensitizer from endosomes. In this study, a novel photosensitizer is prepared by combining antraquinone derivatives with strong two-photon absorption and four phenal porphyrin. Effective fluoresence resonance energy transfer between antraquinone derivatives and four phenal porphyrin facilitates the potosensitizer to produce singlet oxygen with high efficiency. A novel ternary component nano delivery system (TCNDS) are formed by using protein with charge reversal function in endosome, amphiphilic polycation with folate as targeting group and photosensitizer. The folate can guarantee TCNDS to be delivered into certain tumor tissue with high efficiency. Protein with charge reversal ability in endosome can facilitate amphiphilic polycation/photosensitizer nanoparticles to escape endosome. Delivery performance of the photosensitizer by TCNDS and photodynamic therapy behavior for tumor cells are studied. This research will greatly increase the production efficiency of singlet oxygen of photosensitizer and improve the killing effect of TPPDT on tumor cells.

双光子激发光动力治疗（TPPDT）具有深的组织穿透和精准空间定位能力，有望实现普通光动力治疗难以实现的深层肿瘤的有效治疗。但是，TPPDT光敏剂双光子激发单线态氧产生效率低、肿瘤组织靶向性差及内涵体逃逸能力差是需要亟待解决的科学问题。申请人将具有强双光子吸收的蒽醌衍生物与卟啉类光敏剂四苯基卟吩组合制备新型光敏剂，两者之间的荧光共振能量转移使该新型光敏剂双光子激发下高效的产生单线态氧。采用内涵体环境具有电荷反转功能的蛋白、端基带叶酸靶向基团的两亲性聚阳离子和光敏剂构建三元复合纳米递送系统（TCNDS），叶酸可使TCNDS高效递送光敏剂至特定肿瘤组织，具有电荷反转功能的蛋白可增强两亲性聚阳离子/光敏剂二元复合纳米粒内涵体逃逸能力。研究TCNDS递送光敏剂的性能和肿瘤细胞的光动力杀伤行为。本项目的研究对于解决TPPDT光敏剂单线态氧产生效率低、提高TPPDT对肿瘤细胞的杀伤效果具有重要意义。

双光子激发光动力治疗（TPPDT）具有深的组织穿透和精准空间定位能力，有望实现普通光动力治疗难以实现的深层肿瘤的有效治疗。但是， TPPDT 光敏剂双光子激发单线态氧产生效率低、 肿瘤组织靶向性差及内涵体逃逸能力差是需要亟待解决的科学问题。本项目重点针对单线态氧的问题，发展了提高单线态氧产生效率的一系列方法。首先研究了980nm激发的上转换纳米粒子（UCNPs）的合成工艺对UCNPs的影响以及如何提高UCNPs的荧光强度和亲水性问题。在之前的基础上制备了808 nm的激光的UCNPs，负载光敏剂MB之后通过二氧化硅包覆研究单线态氧的产生情况，通过改变纳米粒壳层厚度得到不同的单线态氧产量，发展了有效提高单线态效率的方法。进一步制备了不同结构与组成的UCNPs，测试并比较其上转换荧光强度，通过介孔硅改性UCNPs、共价键链接光敏剂的方法，构建了稳定高效的纳米光敏体系。通过控制UCNPs的壳层厚度可以有效的调控其与光敏剂的荧光共振能量转移（FRET）的效率。壳层厚度最薄的FRET效率高达86.7 %。单线态氧测试结果表明壳层厚度越薄的样品其单线态氧的产量越高，该体系同时实现了高的上转换荧光发射强度和高的FRET效率，最终使得单线态氧的产量得到大幅度提高。通过调控壳层中的稀土元素组成研究了不同壳层组成的UCNPs制备的样品在808 nm 和980 nm激光下单线态氧的产生情况，当以808 nm激光作为激发光源，采用具有最佳壳层组成的样品（NaYF4:Yb,Er,Nd@NaYF4:Yb0.1Nd0.2）制备UCNPs@mSiO2-Ce6时，单线态氧的产生效率最高，实现了高效纳米光敏体系的构建。 本项目的研究对于解决 TPPDT 光敏剂单线态氧产生效率低、提高 TPPDT 对肿瘤细胞的杀伤效果具有重要意义。