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Cancer‐Targeting Graphene Quantum Dots: Fluorescence Quantum Yields, Stability, and Cell Selectivity
Author(s) -
Zhang Qing,
Deng Sinan,
Liu Jinlin,
Zhong Xiaoxia,
He Jie,
Chen Xianfeng,
Feng Bowen,
Chen Yanfei,
Ostrikov Kostya Ken
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201805860
Subject(s) - materials science , graphene , quantum dot , fluorescence , cancer cell , nanotechnology , folate receptor , luminescence , solubility , folic acid , receptor , photochemistry , combinatorial chemistry , cancer , optoelectronics , chemistry , organic chemistry , biochemistry , biology , medicine , physics , quantum mechanics , genetics
Folic acid, due to its high affinity toward folate receptors (FR), is recognized as one of the most promising cancer targeting vectors. However, the inherent defects of low water solubility (1.6 µg mL −1 ), high sensitivity toward photo‐bleaching, low fluorescent quantum yields (QYs, <0.5%) seriously limit its practical application. Herein, ultrastable, highly luminescent graphene quantum dots (GQDs) that selectively target diverse cancer cells are prepared and tested. The new GQDs present step changes compared to common folic acid through an ≈6250 times increase in water solubility (to ≈10 mg mL −1 ), more than 150 times in QYs (up to ≈77%), while maintaining luminescence stability up to 98% when subjected to UV, visible light, and heating over 360 min. It is shown that the suppression of nonradiative transitions by amino groups pyrolyzed from pterin plays a key role in the mechanism of high QYs and excellent stability. The functional groups that are likely responsible for the selective targeting of cancer cells with different levels of folate receptor expression on the surface are identified. Collectively with these promising properties, the new functional graphene quantum dots may open a new avenue for cancer diagnosis, drug delivery, and therapies.