Timor Reut, Weitman Hana, Waiskopf Nir, Banin Uri, Ehrenberg Benjamin
Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar Ilan University , Ramat Gan 52900, Israel.
Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.
ACS Appl Mater Interfaces. 2015 Sep 30;7(38):21107-14. doi: 10.1021/acsami.5b04318. Epub 2015 Sep 18.
Singlet oxygen ((1)O2) generated upon photostimulation of photosensitizer molecules is a highly reactive specie which is utilized in photodynamic therapy. Recent studies have shown that semiconductor nanoparticles can be used as donors in fluorescence resonance energy transfer (FRET) process to excite attached photosensitizer molecules. In these studies, their unique properties, such as low nanoscale size, long-term photostability, wide broad absorbance band, large absorption cross section, and narrow and tunable emission bands were used to provide advantages over the traditional methods to produce singlet oxygen. Previous studies that achieved this goal, however, showed some limitations, such as low FRET efficiency, poor colloidal stability, nonspecific interactions, and/or complex preparation procedure. In this work, we developed and characterized a novel system of semiconductor quantum rods (QRs) and the photosensitizer meso-tetra(hydroxyphenyl) chlorin (mTHPC), as a model system that produces singlet oxygen without these limitations. A simple two-step preparation method is shown; Hydrophobic CdSe/CdS QRs are solubilized in aqueous solutions by encapsulation with lecithin and PEGylated phospholipid (PEG-PL) of two lipid lengths: PEG350 or PEG2000. Then, the hydrophobic photosensitizer mTHPC, was intercalated into the new amphiphilic PEG-PL coating of the QR, providing a strong attachment to the nanoparticle without covalent linkage. These PEGylated QR (eQR)-mTHPC nanocomposites show efficient FRET processes upon light stimulation of the QR component which results in efficient production of singlet oxygen. The results demonstrate the potential for future use of this concept in photodynamic therapy schemes.
光敏剂分子受光刺激产生的单线态氧（(1)O2）是一种高活性物质，可用于光动力疗法。最近的研究表明，半导体纳米颗粒可作为荧光共振能量转移（FRET）过程中的供体，以激发附着的光敏剂分子。在这些研究中，它们独特的性质，如纳米级尺寸小、长期光稳定性、宽吸收带、大吸收截面以及窄且可调谐的发射带，被用于提供优于传统单线态氧产生方法的优势。然而，此前实现这一目标的研究显示出一些局限性，如FRET效率低、胶体稳定性差、非特异性相互作用和/或制备过程复杂。在这项工作中，我们开发并表征了一种新型的半导体量子棒（QR）与光敏剂中-四（羟苯基）氯卟啉（mTHPC）的体系，作为一个不存在这些局限性的单线态氧产生模型体系。展示了一种简单的两步制备方法；疏水性的CdSe/CdS量子棒通过用卵磷脂和两种脂质长度（PEG350或PEG2000）的聚乙二醇化磷脂（PEG-PL）包封而溶解于水溶液中。然后，将疏水性光敏剂mTHPC插入量子棒新的两亲性PEG-PL涂层中，在不进行共价连接的情况下与纳米颗粒形成牢固附着。这些聚乙二醇化量子棒（eQR）-mTHPC纳米复合材料在光刺激量子棒组分时显示出高效的FRET过程，从而高效产生单线态氧。结果证明了这一概念在未来光动力疗法方案中的应用潜力。
