White-Light-Emitting Carbon Nano-Onions: A Tunable Multichannel Fluorescent Nanoprobe for Glutathione-Responsive Bioimaging

Abstract

Although white-light-emitting nanomaterials are capable of generating multichannel fluorescence emissions, their acute toxicity in the biological system limited their biomedical applications. This article details the fabrication of water-soluble, biocompatible, single-phosphor white-light-emitting carbon nano-onions (WCNOs) and presents them as a novel multichannel fluorescence nanoprobe for bioimaging and biosensing applications. FE-TEM results confirmed the fabrication of WCNOs. In vitro and in vivo studies confirmed the uptake and multichannel fluorescence emissions from WCNOs in all three primitive channels (blue, green, and red). Furthermore, WCNOs showed increased tumor accumulation, with a safe elimination through the liver and kidneys. For further investigation of their application as a stimuli-responsive functional nanoprobe, the surfaces of WCNOs were coated with manganese oxide (WCNO-MnO2) nanosheets, which not only quenched the fluorescence of WCNO, but also reacted with the glutathione (GSH) in the biological environments. Results showed that GSH can etch the MnO2 on the surface of WCNO-MnO2 and aid in the GSH-responsive fluorescence recovery from WCNOs. In vitro and in vivo results further demonstrated GSH-responsive multichannel bioimaging from WCNO-MnO2. These results confirmed WCNOs as a novel, biocompatible multichannel fluorescence nanoprobe, that can be used for diverse biomedical applications.

Carbon Nano‐Onions: A Review of Recent Progress in Synthesis and Applications

“…Composites containing “small” spherical CNOs and inorganic species such as metal hydroxides or oxides (MnO 2 , Ni(OH) 2 or NiO,, RuO 2 ,, CuO and Co 3 O 4 ) were investigated. CNOs and nickel hydroxide were prepared by a precipitation method with three different mass ratios of both components.…”

“…The CNO hybrid systems were used as materials for hybrid charge‐storage devices ,. This type of modification was also applied to the preparation of CNO/RuO 2 ,, CNO/MnO 2 ,, and CNO/CuO composites ,,. A novel composite of CNO/Co 3 O 4 was synthesized using ionic liquid as a carbon and nitrogen source through a facile carbothermic reduction followed by a low‐temperature oxidation method .…”

Supramolecular chemistry of carbon nano-onions

“…This etching of the metallic coating thus restored the WCNOs fluorescence properties. The results of this study indicated that WCNOs non-covalently coated in metallic nanosheets have the potential for use in biosensing and nanomedicine 32 . Also in 2018, Fragoso et al explored the use of crown ethers and aminated, biocompatible polymers to create a dispersible supramolecular, CNO-based system.…”

“…In general, CNOs show low-cytotoxicity and great biocompatibility across many biological systems. In vitro assays of various functionalised CNOs (f-CNOs) have been carried out on various cell lines, showing good results -these included cytotoxicity assays of MCF-7 cells 26 , HeLa cells [27][28][29][30] , HeLa Kyoto cells 31 , 4T1 cells 32 , and KB cells 27 . Moreover, f-CNOs have also shown good biocompatibility with fresh-water polyps (Hydra vulgaris) 33 , common fruit flies (Drosophila melanogaster) 34 , and zebrafish (Danio rerio) 35,36 .…”

Two-dimensional nanomaterials for Förster resonance energy transfer–based sensing applications

“…As discussed above, most TMD-based FRET sensors exploit the differential affinity of TMDs toward probes and the probe-target combination. Unlike other TMDs, the MnO 2 nanosheets are chemically active and could be reduced into Mn 2+ , which makes them good candidates in constructing novel FRET sensors for the detection of reductants, especially GSH, the most abundant thiolated tripeptide in living cells [38,[121][122][123][124][125][126][127][128][129][130][131][132][133][134][135][136]. The first study was carried out by Deng et al [38].…”