Near-infrared (NIR) long lasting persistent luminescence nanoparticles (PLNPs) have attracted considerable attention in the area of in vivo bioimaging, due to their background-free luminescence characteristics and deep tissue penetration. However, the low fluorescence quantum yield and short afterglow of the currently available PLNPs limit their applications. Here, water-soluble Cr³⁺-doped ZnGa₂O₄ PLNPs with the highest quantum yield (η = 20%) ever reported, bright NIR emission, and excellent colloidal stability were successfully prepared by a one-step hydrothermal method. The afterglow of the resultant nanocrystals lasted for more than 5 days and could be repeatedly reactivated by the light (λ = 657 nm) of a portable light emitting diode lamp after decay. These nanocrystals were functionalized with α,ω-dicarboxyl-terminated poly(ethylene glycol) and poly(acrylic acid) to improve their stability and biocompatibility, so that they could be conjugated with a c(RGDyK) peptide and labeled with ^99mTc for targeted imaging of orthotopic breast cancer by afterglow luminescence imaging and single-photon emission computed tomography imaging. Our NIR-PLNP probes can effectively avoid tissue auto-fluorescence and the light scattering caused by continuous excitation during the diagnosis of cancer.

中文翻译：

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口服高亮度Cr ³⁺掺杂的ZnGa ₂ O ₄纳米晶体，用于原位乳腺癌的体内靶向成像†

由于近红外（NIR）持久发光纳米颗粒（PLNP）的无背景发光特性和深层组织穿透性，在体内生物成像领域引起了相当大的关注。然而，目前可用的PLNP的低荧光量子产率和短余辉限制了它们的应用。在此，通过一步水热法成功地制备了有史以来报道的量子产率最高（η = 20％），NIR发光明亮，胶体稳定性极佳的水溶性Cr ³⁺掺杂ZnGa ₂ O ₄ PLNP 。产生的纳米晶体的余辉持续了超过5天，并且可以被光重复激活（λ= 657 nm）衰减后的便携式发光二极管灯。这些纳米晶体用α，ω-二羧基封端的聚乙二醇和聚丙烯酸官能化以提高其稳定性和生物相容性，因此可以与ac（RGDyK）肽缀合并用^99m Tc标记以进行靶向成像余辉发光成像和单光子发射计算机断层扫描成像对原位乳腺癌的诊断 我们的NIR-PLNP探针可有效避免组织自体荧光和在癌症诊断过程中由于连续激发而引起的光散射。