State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University , 2 Sipailou Road, Nanjing 210096, P. R. China.
Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109, United States.
Biomacromolecules. 2017 Oct 9;18(10):3073-3081. doi: 10.1021/acs.biomac.7b00725. Epub 2017 Sep 8.
Benefiting from their inherent localized and controlled release properties, hydrogels are ideal delivery systems for therapeutic drugs or nanoparticles. In particular, applications of hydrogels for the delivery and release of photoresponsive drugs or nanoparticles are receiving increasing attention. However, the effect of the hydrogel matrix on the fluorescence emission and singlet oxygen generation efficiency of the embedded photosensitizers (PSs) has not been clarified. Herein, meso-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP) as a water-soluble PS was encapsulated into an injectable hydrogel formed by glycol chitosan and dibenzaldehyde-terminated telechelic poly(ethylene glycol). Compared to free TMPyP solution, the TMPyP encapsulated in the hydrogel exhibits three distinct advantages: (1) more singlet oxygen was generated under the same laser irradiation condition; (2) much longer tumor retention was observed due to the low fluidity of the hydrogel; and (3) the fluorescence intensity of TMPyP was significantly enhanced in the hydrogel due to its decreased self-quenching effect. These excellent characteristics lead to remarkable anticancer efficacy and superior fluorescence emission property of the TMPyP-hydrogel system, promoting the development of imaging-guided photodynamic therapy.
得益于其固有的局部控制释放特性，水凝胶是治疗药物或纳米颗粒的理想输送系统。特别是，水凝胶在光响应药物或纳米颗粒的输送和释放中的应用受到越来越多的关注。然而，水凝胶基质对嵌入光敏剂（PSs）的荧光发射和单线态氧生成效率的影响尚未阐明。在此，作为一种水溶性 PS 的间四（1-甲基吡啶-4-基）卟啉（TMPyP）被包封到由乙二醇壳聚糖和二苯甲醛封端的遥爪聚乙二醇形成的可注射水凝胶中。与游离 TMPyP 溶液相比，包封在水凝胶中的 TMPyP 具有三个明显的优势：（1）在相同的激光照射条件下生成更多的单线态氧；（2）由于水凝胶的低流动性，观察到更长的肿瘤保留时间；（3）由于自猝灭效应降低，TMPyP 在水凝胶中的荧光强度显著增强。这些优异的特性导致 TMPyP-水凝胶系统具有显著的抗癌功效和优异的荧光发射特性，促进了成像引导光动力疗法的发展。
