Key Laboratory of Low-dimensional Quantum Structures and Quantum Control of the Ministry of Education, College of Physics and Information Science, and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University , Changsha, Hunan 410081, China.
Department of Applied Physics, The Hong Kong Polytechnic University , Hong Kong, China.
ACS Appl Mater Interfaces. 2017 Jul 12;9(27):22132-22142. doi: 10.1021/acsami.7b03802. Epub 2017 Jun 26.
Near-infrared (NIR) persistent luminescence nanoparticles (PLNPs) are considered as new alternative optical probes due to being free of autofluorescence, benefited from the self-sustained emission after excitation and high signal-to-noise ratio. However, the NIR-emitted PLNPs always present a short decay time and require excitation by ultraviolet or visible light with a short penetrable depth, remarkably hindering their applications for in vivo long-term tracking and imaging. Therefore, it is important to develop NIR-emitted PLNPs with in vivo activation nature by new excitation sources with deeper penetrating depths. Here, we propose a new type of X-ray-activated ZnGaO:Cr PLNPs (X-PLNPs) with efficient NIR persistent emission and rechargeable activation features, in which both the excitation and emission possess a high penetrable nature in vivo. These X-PLNPs exhibit long-lasting, up to 6 h, NIR emission at 700 nm after the stoppage of the X-ray excitation source. More importantly, the designed X-PLNPs can be readily reactivated by a soft X-ray excitation source with low excitation power (45 kVp, 0.5 mA) to restore in vivo bioimaging signals even at 20 mm depth. Renewable in vivo whole-body bioimaging was also successfully achieved via intravenous injection/oral administration of X-PLNPs after in situ X-ray activation. This is the first time that NIR-emitted PLNPs have been demonstrated to be recharged by X-ray light for deep-tissue in vivo bioimaging, which paves the way for in vivo renewable bioimaging using PLNPs and makes the PLNPs more competitive in bioimaging area.
近红外（NIR）持续发光纳米粒子（PLNPs）由于无自发荧光，受益于激发后的自持续发射和高信噪比，被认为是新的替代光学探针。然而，NIR 发射的 PLNPs 总是表现出短的衰减时间，并且需要用紫外光或可见光激发，穿透深度短，这显著阻碍了它们在体内长期跟踪和成像中的应用。因此，开发具有体内激活特性的 NIR 发射 PLNPs 是非常重要的，其新的激发源具有更深的穿透深度。在这里，我们提出了一种新型的 X 射线激活的 ZnGaO:Cr PLNPs（X-PLNPs），具有高效的 NIR 持续发射和可再充电的激活特性，其中激发和发射在体内都具有高穿透性。这些 X-PLNPs 在 X 射线激发源停止后，表现出长达 6 小时的持久的 700nm NIR 发射。更重要的是，设计的 X-PLNPs 可以很容易地被低激发功率（45 kVp，0.5 mA）的软 X 射线激发源重新激活，以恢复体内生物成像信号，即使在 20mm 深度。通过原位 X 射线激活后静脉注射/口服 X-PLNPs，还成功实现了可再生的体内全身生物成像。这是首次证明 NIR 发射的 PLNPs 可以通过 X 射线光再充电，用于体内深层组织生物成像，为使用 PLNPs 进行体内可再生生物成像铺平了道路，并使 PLNPs 在生物成像领域更具竞争力。
