Graphene‐Oxide‐Modified Lanthanide Nanoprobes for Tumor‐Targeted Visible/NIR‐II Luminescence Imaging

Abstract

The synthesis of hydrophilic lanthanide‐doped nanocrystals (Ln3+‐NCs) with molecular recognition ability for bioimaging currently remains a challenge. Herein, we present an effective strategy to circumvent this bottleneck by encapsulating Ln3+‐NCs in graphene oxide (NCs@GO). Monodisperse NCs@GO was prepared by optimizing GO size and core–shell structure of NaYF4:Yb,Er@NaYF4, thus combining the intense visible/near‐infrared II (NIR‐II) luminescence of NCs and the unique surface properties and biomedical functions of GO. Such nanostructures not only feature broad solvent dispersibility, efficient cell uptake, and excellent biocompatibility but also enable further modifications with various agents such as DNA, proteins, or nanoparticles without tedious procedures. Moreover, we demonstrate in proof‐of‐concept experiments that NCs@GO can realize simultaneous intracellular tracking and microRNA‐21 visualization, as well as highly sensitive in vivo tumor‐targeted NIR‐II imaging at 1525 nm.

Activatable fluorescence sensors forin vivobio-detection in the second near-infrared window

“…As mentioned in Section 2.2, most inorganic nanoparticles, including quantum dots (QDs) and lanthanide-doped nanoparticles, are hardly individually used for bio-sensing due to their non-responsive property. 57,[63][64][65][66] Nevertheless, their robust spectral properties provide them an opportunity as the stable donors in energy transfer systems or the calibrated reference signal in ratiometric uorescent/luminescent imaging systems. 67,68 In contrast, organic dyes with relatively weak chemical and structural stabilities are suitable to serve as responsive detection signals, respectively.…”

DNA Triplex and Quadruplex Assembled Nanosensors for Correlating K+ and pH in Lysosomes

“…[11] Furthermore,UCNPs have been used as labels for imaging miRNA, metal ions and pH. [12] In this work, we constructed two DNA-assembled and nanoparticle-based biosensors and used them for lysosomal imaging for answering the acidification question.…”

An efficient synthetic strategy for ligand-free upconversion nanoparticles

“…1 In stark contrast to semiconductor quantum dots and organic dyes, upconversion nanoparticles feature excellent chemical and optical properties, including large anti-Stokes shifts, long fluorescence lifetimes, sharp multicolour emissions, low cytotoxicity, as well as high chemical-and photo-stability. 2 Based on these outstanding merits, upconversion nanoparticles are regarded as promising luminescent materials for applications in photodynamic therapy, [3][4][5][6] bioimaging, [7][8][9] sensing, [10][11][12][13] anticounterfeiting, 14,15 and other optical fields. 16 High-quality upconversion nanoparticles with precisely tuned size, composition, shape, and well-designed architecture are generally synthesized by applying the long-chain oleic acid (OA) as the ligand in the synthetic process.…”