National Institute of Laser Enhanced Science, Cairo University, Egypt.
Nanotechnology and Advanced Materials Central Lab, Agriculture Research Center, El Gamaa St., Giza, Egypt.
Photodiagnosis Photodyn Ther. 2021 Sep;35:102444. doi: 10.1016/j.pdpdt.2021.102444. Epub 2021 Jul 17.
Chlorophyll, the essential green pigment in plants, is considered a promising natural photosensitizer (PS) for photodynamic therapy (PDT). However, it suffers from lower stability in the physiological conditions that depress its efficacy in the PDT. The combination of nanotechnology and PDT is becoming a promising approach to combat tumors. Gold nanoparticles (Au NPs), for example, are proposed as suitable carriers that can increase chlorophyll stability when conjugating together. In the present work, the impact of Au NPs conjugation in enhancing Chlorophyll b (Chl b) efficiency in the PDT of cancer cells has been emphasized. A chemical method using a natural product synthesized a novel Chlorophyll b-gold nanoparticles nanoconjugate (Chl b-Au NCs). The synthesized Chl b-Au NCs were characterized via UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Laser-Induced Fluorescence (LIF), Zeta potential, Dynamic light scattering (DLS), and Transmission electron microscopy (TEM). Chl b is characterized by a formyl group (CHO) which is absent in Chl a. This group leads to the formation of an electrostatic reaction between the positive charge of Chl b and the negative charge present on the surface of the gold nanoparticles. Moreover, Chlorophyll b loading on the biosynthesized gold nanoparticles (Au NPs) increases its photostability. The efficiency of the PDT was then studied on the MCF7 and the HepG2 cells using this conjugation. As a result, the prepared Chl b-Au NCs showed low dark toxicity, excellent photostability under laser irradiation of wavelength 650 nm, in addition to a significantly high PDT efficacy against tumor cells in vitro. This is due to the enhanced cellular uptake and the high reactive oxygen species (ROS) production upon laser irradiation. Therefore, the designed Chl b-Au NCs could be a photo-therapeutic agent for enhancing cancer therapy in future applications.
叶绿素是植物中必不可少的绿色色素，被认为是一种很有前途的天然光敏剂（PS），可用于光动力疗法（PDT）。然而，在抑制其 PDT 疗效的生理条件下，它的稳定性较差。纳米技术与 PDT 的结合正成为对抗肿瘤的一种有前途的方法。例如，金纳米粒子（Au NPs）被提议作为合适的载体，与叶绿素结合时可以提高其稳定性。在本工作中，强调了 Au NPs 结合对提高癌细胞 PDT 中叶绿素 b（Chl b）效率的影响。一种使用天然产物合成的化学方法合成了一种新型的叶绿素 b-金纳米粒子纳米复合物（Chl b-Au NCs）。通过紫外可见光谱、傅里叶变换红外光谱（FTIR）、激光诱导荧光（LIF）、Zeta 电位、动态光散射（DLS）和透射电子显微镜（TEM）对合成的 Chl b-Au NCs 进行了表征。Chl b 的特征是存在一个甲酰基（CHO），而 Chl a 中不存在该基团。该基团导致 Chl b 的正电荷与金纳米粒子表面存在的负电荷之间形成静电反应。此外，叶绿素 b 负载在生物合成的金纳米粒子（Au NPs）上会增加其光稳定性。然后，使用这种结合物在 MCF7 和 HepG2 细胞上研究 PDT 的效率。结果表明，所制备的 Chl b-Au NCs 在黑暗中毒性低，在波长为 650nm 的激光照射下具有优异的光稳定性，并且在体外对肿瘤细胞具有显著的高 PDT 疗效。这是由于细胞摄取增强和激光照射下产生的高活性氧（ROS）。因此，设计的 Chl b-Au NCs 可以成为一种光疗剂，用于增强未来应用中的癌症治疗。
