Near-IR photoactivation using mesoporous silica-coated NaYF4:Yb,Er/Tm upconversion nanoparticles
Near-IR photoactivation using mesoporous silica-coated NaYF4:Yb,Er/Tm upconversion nanoparticles
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DOI：
10.1038/nprot.2016.035
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发表时间：
2016-04-01
期刊：
影响因子：
14.8
通讯作者：
Zhang, Yong
中科院分区：
文献类型：
--
作者：
Gnanasammandhan, Muthu Kumara;Idris, Niagara Muhammad;Zhang, Yong
光激活是利用光“激活”光不稳定疗法的过程。作为一种治疗策略，其优点是非侵入性并且可以实现高度的空间和时间控制。然而，传统的光活化技术受到光敏化合物响应的紫外光和可见光的有限穿透深度的阻碍。在这里，我们描述了一种使用上转换纳米粒子（UCN）作为光传感器的协议，将深度穿透的近红外（NIR）光转换为与光敏疗法的吸收光谱相匹配的紫外-可见波长。这使得可以使用具有深度穿透性和生物友好性的近红外光来代替低穿透性和/或有毒的可见光或紫外光来进行光激活。在该协议中，我们重点关注两种光激活应用：光动力疗法（PDT）和基因表达的光激活控制。我们描述了如何制备和表征 UCN，以及如何检查它们在生化测定和细胞中的功能。对于这两种应用，UCN 都涂有介孔二氧化硅，以便于装载治疗剂。对于 PDT，UCN 涂有聚乙二醇（PEG）以保持稳定性，并涂有叶酸以靶向肿瘤，然后装载光敏剂，预计通过产生单线态氧来杀死细胞；纳米颗粒被静脉注射。对于基因表达的光激活控制，使用装载有笼状核酸的 UCN 实现肿瘤必需基因的敲低，这些核酸被注射到肿瘤内。从纳米粒子合成到动物研究的整个过程大约需要36天。
Photoactivation is a process in which light is used to 'activate' photolabile therapeutics. As a therapeutic strategy, its advantages are that it is noninvasive and that a high degree of spatial and temporal control is possible. However, conventional photoactivation techniques are hampered by the limited penetration depth of the UV and visible lights to which the photosensitive compounds are responsive. Here we describe a protocol for the use of upconversion nanoparticles (UCNs) as light transducers to convert deeply penetrating near-infrared (NIR) light to UV-visible wavelengths matching that of the absorption spectrum of photosensitive therapeutics. This allows the use of deep-penetrating and biologically friendly NIR light instead of low-penetrating and/or toxic visible or UV lights for photoactivation. In this protocol, we focus on two photoactivation applications: photodynamic therapy (PDT) and photoactivated control of gene expression. We describe how to prepare and characterize the UCNs, as well as how to check their function in biochemical assays and in cells. For both applications, the UCNs are coated with mesoporous silica for easy loading of the therapeutics. For PDT, the UCNs are coated with polyethylene glycol (PEG) for stabilization and folic acid for tumor targeting and then loaded with photosensitizers that would be expected to kill cells by singlet oxygen production; the nanoparticles are injected intravenously. For photoactivated control of gene expression, knockdown of essential tumor genes is achieved using UCNs loaded with caged nucleic acids, which are injected intratumorally. The whole process from nanoparticle synthesis to animal studies takes similar to 36 d.