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Rare‐Earth Metal Ions Doped Graphene Quantum Dots for Near‐IR In Vitro/In Vivo/Ex Vivo Imaging Applications
Author(s) -
Hasan Md. Tanvir,
GonzalezRodriguez Roberto,
Lin ChingWei,
Campbell Elizabeth,
Vasireddy Satvik,
Tsedev Uyanga,
Belcher Angela M.,
Naumov Anton V.
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202000897
Subject(s) - materials science , biocompatibility , ex vivo , graphene , fluorescence , nanomaterials , in vivo , nanotechnology , quantum dot , fluorescence lifetime imaging microscopy , preclinical imaging , biocompatible material , biomedical engineering , optics , medicine , microbiology and biotechnology , metallurgy , biology , physics
Near‐infrared (NIR) emitting biocompatible nanomaterials are desired in biotechnology as higher penetration depth fluorescence imaging probes. In this work, novel NIR‐emissive Nd 3+ ‐doped or Tm 3+ ‐doped biocompatible graphene quantum dots (GQDs) are developed via scalable, single‐step bottom‐up synthesis. Water‐soluble Nd‐GQDs/Tm‐GQDs with average diameters of 5.6–8.2 nm possess crystalline graphene lattice with < 1 atomic percent of Nd/Tm and exhibit NIR fluorescence at ≈ 1060/ ≈ 925 nm attributed to the intrinsic transitions of Nd 3+ /Tm 3+ . High biocompatibility with > 80% cell viability at 1 mg mL −1 for Nd‐GQDs and 0.25 mg mL −1 for Tm‐GQDs makes them well‐suited for bioimaging. In vitro, both GQD types exhibit efficient internalization with their intracellular emission maximized at 6 h. The pH‐dependence of this emission can serve as plethora of diagnostic applications. GQDs enable in vivo NIR imaging in live sedated NCr nude mice with IV administration: their NIR emission maximized at 6 h post‐injection is primarily detected in intestine, kidneys, liver, and spleen, however, diminishing to none at 48 h. Ex vivo organ/slice imaging shows significant Tm‐GQD fluorescence signatures in the aforementioned organs/slices. This capability of NIR fluorescence imaging in cells, tissues, and real‐time detection in live animals makes biocompatible rare‐earth metal‐doped GQDs an attractive new candidate for in vitro/in vivo/ex vivo theranostics.