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Veratryl alcohol can be oxidized to veratryl aldehyde or veratric acid with excellent selectivity and efficient conversion under acidic and alkaline conditions using Au nanoparticles and graphene quantum dot composites (Au/GQDs) as catalysts.

Due to the high peroxidase-like activity and small lateral size of graphene quantum dots (GQDs), the covalently assembled GQDs/Au electrode exhibits great performance and stability in H(2)O(2) detection. It is better or comparable to some enzyme-immobilized electrodes, and thus could be useful in sensing H(2)O(2) changes in biological systems.

Graphene quantum dots (GQDs) are great promising in various applications owing to the quantum confinement and edge effects in addition to their intrinsic properties of graphene, but the preparation of the GQDs in bulk scale is challenging. We demonstrated in this work that the micrometer sized graphene oxide (GO) sheets could react with Fenton reagent (Fe(2+)/Fe(3+)/H(2)O(2)) efficiently under an UV irradiation, and, as a result, the GQDs with periphery carboxylic groups could be generated with mass scale production. Through a variety of techniques including atomic force microscopy, X-ray photoelectron spectroscopy, gas chromatography, ultraperformance liquid chromatography-mass spectrometry, and total organic carbon measurement, the mechanism of the photo-Fenton reaction of GO was elucidated. The photo-Fenton reaction of GO was initiated at the carbon atoms connected with the oxygen containing groups, and C-C bonds were broken subsequently, therefore, the reaction rate depends strongly on the oxidization extent of the GO. Given the simple and efficient nature of the photo-Fenton reaction of GO, this method should provide a new strategy to prepare GQDs in mass scale. As a proof-of-concept experiment, the novel DNA cleavage system using as-generated GQDs was constructed.

Inorganic perovskite quantum dots CsPbX3 (X = Cl, Br, and I) has recently received extensive attention as a new promising class of X‐ray scintillators. However, relatively low light yield (LY) of CsPbX3 and strong optical scattering of the thick opaque scintillator film restrict their practical applications for high‐resolution X‐ray microscopic imaging. Here, the Ce3+ ion doped CsPbBr3 nanocrystals (NCs) with enhanced LY and stability are obtained and then the ultrathin (30 µm) and transparent scintillator films with high density are prepared by a suction filtration method. The small amount Ce3+ dopant greatly enhances the LY of CsPbBr3 NCs (about 33 000 photons per MeV), which is much higher than that of bare CsPbBr3 NCs. Moreover, the scintillator films made by these NCs with high density realize a high spatial resolution of 862 nm thanks to its thin and transparent feature, which is so far a record resolution for perovskite scintillator‐based X‐ray microscopic imaging. This strategy not only provides a simple way to increase the resolution down to nanoscale but also extends the application of as‐prepared CsPbBr3 scintillator for high resolution X‐ray microscopic imaging. [ABSTRACT FROM AUTHOR]

Nanocomposites of graphene quantum dots and Au nanoparticles (GQDs/Au) are immobilized on the Fe 3 O 4 nanoparticles, forming GQDs/Au/Fe 3 O 4 ternary composites. The as-prepared ternary composites exhibit superparamagnetic property rendering them easy to be isolated from the reaction mixture. More importantly, they show superb catalytic activity for solvent-free oxidation of VA and other alcohols that contain an aromatic benzyl group, to the corresponding aldehydes exclusively with air as oxidant. The great stability and selectivity of the GQDs/Au/Fe 3 O 4 indicate that they might be applicable catalysts for the oxidation of aromatic alcohols. [ABSTRACT FROM AUTHOR]

Spherical nucleic acid (SNA) nanoparticle conjugates are a class of bionanomaterials that are extremely potent in many biomedical applications. Their unique ability to enter multiple mammalian cell types as single-entity agents arises from their novel three-dimensional architecture, which consists of a dense shell of highly oriented oligonucleotides chemically attached typically to a gold nanoparticle core. This architecture allows SNAs to engage certain cell surface receptors to facilitate entry. Here, we report studies aimed at determining the intracellular fate of SNAs and the trafficking events that occur inside C166 mouse endothelial cells after cellular entry. We show that SNAs traffic through the endocytic pathway into late endosomes and reside there for up to 24 h after incubation. Disassembly of oligonucleotides from the nanoparticle core is observed 16 h after cellular entry, most likely due to degradation by enzymes such as DNase II localized in late endosomes. Our observations point to these events being likely independent of core composition and treatment conditions, and they do not seem to be particularly dependent upon oligonucleotide sequence. Significantly and surprisingly, the SNAs do not enter the lysosomes under the conditions studied. To independently track the fate of the particle core and the fluorophore-labeled oligonucleotides that comprise its shell, we synthesized a novel class of quantum dot SNAs to determine that as the SNA structures are broken down over the 24 h time course of the experiment, the oligonucleotide fragments are recycled out of the cell while the nanoparticle core is not. This mechanistic insight points to the importance of designing and synthesizing next-generation SNAs that can bypass the degradation bottleneck imposed by their residency in late endosomes, and it also suggests that such structures might be extremely useful for endosomal signaling pathways by engaging receptors that are localized within the endosome. [ABSTRACT FROM AUTHOR]

(A)TEM image of lysozyme. (B) Chemical modification illustration of GOQDs. Images of lysozyme after incubation with (C) 20 μg/mL and (D) 40 μg/mL of GOQDs. Lysozyme aggregated to form amyloid fibrils. GOQDs were enriched with –OH and –COOH to evaluate the influence of the functional groups on amyloid inhibition. The results showed that the electrostatic interaction may play a dominate role comparing to hydrophobic interaction in our situation. [Display omitted] • The interaction between graphene oxide and amyloid proteins was distinct depending on the physical and chemical properties of both amyloid and graphene oxide. • In this paper, Graphene oxide quantum dots were enriched with –OH and –COOH to evaluate the influence of the functional groups on amyloid inhibition. • We found that the electrostatic interaction may play a dominate role comparing to hydrophobic interaction in our situation. Graphene oxide quantum dots (GOQDs) were enriched with carboxyl and hydroxyl groups, respectively, to characterize their effect on modulating the assembly of lysozyme. The hydroxyl enriched GOQDs showed the strongest inhibition effect for the fibrillation of lysozyme, which may due to the enhanced electrostatic interactions to proteins. [ABSTRACT FROM AUTHOR]