Vejdani Noghreiyan Atefeh, Sazegar Mohammad Reza, Mousavi Shaegh Seyed Ali, Sazgarnia Ameneh
Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Medical Physics, Faculty of Medicine, University of Medical Sciences, Mashhad, Iran.
Department of Chemistry, Islamic Azad University, North Tehran Branch, Hakimiyeh, Tehran, Iran.
Photodiagnosis Photodyn Ther. 2020 Jun;30:101770. doi: 10.1016/j.pdpdt.2020.101770. Epub 2020 Apr 18.
Photodynamic therapy (PDT) has been recognized as an effective method for cancer treatment; however, it suffers from limited tissue penetration depth. X-rays are ideal excitation sources for activating self-lighting nanoparticles that can penetrate through deep tumor tissues and convert the X-rays to visible light. In this study, Ti-MSN/PpIX nanoparticles for X-ray induced photodynamic therapy was synthesized. Preparation, characterization, and emission spectrum of Ti-MSN/PpIX nanoparticles as well as PDT activity and toxicity of the nanoparticles on HT-29 cell line were investigated.
Firstly, mesoporous silica nanoparticles (MSN) were synthesized through sol-gel method. Then, TiO and PpIX were loaded in MSN. Next, the emission spectra of TiO, Ti-MSN, and Ti-MSN/PpIX nanoparticles, while activated by X-ray (6 MV), were recorded. In addition, viability of cells after treatment by Ti-MSN/PpIX nanoparticles and X-ray irradiation was studied.
SEM, TEM and FESEM images of the spherical composite nanoparticles showed that their dimensions were changed by incorporating Ti and organic compound of PpIX. Two-dimensional hexagonal structure with d-spacing was about 3.5 nm with particle sizes of 70-110 nm. The optical characteristics of TiO nanoparticles showed strong emission lines, which effectively overlapped with the absorption wavelengths of protoporphyrin IX (PpIX). Cellular experiments showed Ti-MSN/PpIX nanoparticles have proper biocompatibility, however, after X-ray irradiation, significant decrease of cell viability in the presence of the nanoparticles was observed.
The presented X-PDT method could enhance RT efficacy and is enable that allows for reducing X-ray dose exposure to healthy tissues to overcome radio-resistant tumors.
光动力疗法（PDT）已被公认为一种有效的癌症治疗方法；然而，其组织穿透深度有限。X射线是激活自发光纳米颗粒的理想激发源，这些纳米颗粒可以穿透深部肿瘤组织并将X射线转化为可见光。在本研究中，合成了用于X射线诱导光动力疗法的Ti-MSN/PpIX纳米颗粒。研究了Ti-MSN/PpIX纳米颗粒的制备、表征、发射光谱以及该纳米颗粒对HT-29细胞系的光动力疗法活性和毒性。
首先，通过溶胶-凝胶法合成介孔二氧化硅纳米颗粒（MSN）。然后，将TiO和PpIX负载到MSN中。接下来，记录TiO、Ti-MSN和Ti-MSN/PpIX纳米颗粒在6 MV X射线激活下的发射光谱。此外，研究了Ti-MSN/PpIX纳米颗粒和X射线照射处理后细胞的活力。
球形复合纳米颗粒的扫描电子显微镜（SEM）、透射电子显微镜（TEM）和场发射扫描电子显微镜（FESEM）图像显示，掺入Ti和PpIX有机化合物后其尺寸发生了变化。具有约3.5 nm d间距的二维六方结构，粒径为70-110 nm。TiO纳米颗粒的光学特性显示出强发射线，其与原卟啉IX（PpIX）的吸收波长有效重叠。细胞实验表明，Ti-MSN/PpIX纳米颗粒具有良好的生物相容性，然而，在X射线照射后，观察到存在纳米颗粒时细胞活力显著下降。
所提出的X-PDT方法可以提高放射治疗疗效，并能够减少对健康组织的X射线剂量暴露，以克服放射抗性肿瘤。
