Near-Infrared Carbon Dots With Antibacterial and Osteogenic Activities for Sonodynamic Therapy of Infected Bone Defects.

Repairing infected bone defects is hindered by the presence of stubborn bacterial infections and inadequate osteogenic activity. The incorporation of harmful antibiotics not only fosters the emergence of multidrug-resistant bacteria, but also diminishes the osteogenic properties of scaffold materials. In addition, it is essential to continuously monitor the degradation kinetics of scaffold materials at bone defect sites, yet the majority of bone repair materials lack imaging capability.

Graphene Quantum Dots Eradicate Resistant and Metastatic Cancer Cells by Enhanced Interfacial Inhibition.

Drug-resistant and metastatic cancer cells such as a small population of cancer stem cells (CSCs) play a crucial role in metastasis and relapse. Conventional small-molecule chemotherapeutics, however, are unable to eradicate drug-resistant CSCs owing to limited interface inhibitory effects. Herein, it is reported that enhanced interfacial inhibition leading to eradication of drug-resistant CSCs can be dramatically induced by self-insertion of bioactive graphene quantum dots (GQDs) into DNA major groove (MAG) sites in cancer cells.

Single Atom Catalysts Remodel Tumor Microenvironment for Augmented Sonodynamic Immunotherapy.

The immunosuppressive tumor microenvironment (TME) is a huge hurdle in immunotherapy. Sono-immunotherapy is a new treatment modality that can reverse immunosuppressive TME, but the sonodynamic effects are compromised by overexpressed glutathione (GSH) and hypoxia in the TME. Herein, this work reports a new sono-immunotherapy strategy using Pd single atom catalysts to enhance positive sonodynamic responses to the immunosuppressive and sono-suppressive TME.

N-Heterocycle Modified Graphene Quantum Dots as Topoisomerase Targeted Nanoantibiotics for Combating Microbial Infections.

Developing next-generation antibiotics to eliminate multidrug-resistant (MDR) bacteria/fungi and stubborn biofilms is challenging, because of the excessive use of currently available antibiotics. Herein, the fabrication of anti-infection graphene quantum dots (GQDs) is reported, as a new class of topoisomerase (Topo) targeting nanoantibiotics, by modification of rich N-heterocycles (pyridinic N) at edge sites. The membrane-penetrating, nucleus-localizing, DNA-binding GQDs not only damage the cell walls/membranes of bacteria or fungi, but also inhibit DNA-binding proteins, such as Topo I, thereby affecting DNA replication, transcription, and recombination.

Graphitic-N-doped graphene quantum dots for photothermal eradication of multidrug-resistant bacteria in the second near-infrared window.

Developing efficient therapeutic strategies for combating bacterial infection remains a challenge owing to the indiscriminate utilization of antibiotics and the prevalence of multidrug-resistant (MDR) bacteria. Herein, highly graphitic-N-doped graphene quantum dots (N-GQDs) with efficient NIR-II photothermal conversion properties were synthesized for the first time for photothermal antibacterial therapy. The obtained N-GQDs exhibited strong NIR absorption ranging from 700 to 1200 nm, achieving high photothermal conversion efficiency of 77.

Platinum Crosslinked Carbon Dot@TiO p-n Junctions for Relapse-Free Sonodynamic Tumor Eradication via High-Yield ROS and GSH Depletion.

Sonodynamic therapy as a promising noninvasive modality is being developed for tumor therapy, but there is a lack of next-generation sonosensitizers that can generate full ROS at high yields and simultaneously deplete elevated levels of glutathione (GSH) in tumor cells. Semiconductor p-n junctions are engineered as high-efficacy sonosensitizers for sonodynamic tumor eradication using pyridine N-doped carbon dots (N-CDs) as a p-type semiconductor and oxygen-deficient TiO nanosheets as a n-type semiconductor. The rate constants of O and •OH generation by ultrasound-excited N-CD@TiO p-n junctions are 4.

W-Doped TiO Nanorods for Multimode Tumor Eradication in Osteosarcoma Models under Single Ultrasound Irradiation.

Sonosensitizers play crucial roles in the controlled production of reactive oxygen species (ROS) under ultrasound (US) irradiation with high tissue-penetration depth for noninvasive solid tumor therapy. It is desirable to fabricate structurally simple yet multifunctional sonosensitizers from ultrafine nanoparticles for ROS-based multimode therapy to overcome monomode limitations such as low ROS production yields and endogenous reductive glutathione (GSH) to ROS-based treatment resistance. We report the facile high-temperature solution synthesis of ultrafine W-doped TiO (W-TiO) nanorods for exploration of their sonodynamic, chemodynamic, and GSH-depleting activities in sonodynamic-chemodynamic combination tumor therapy.

Carbon Dot-Passivated Black Phosphorus Nanosheet Hybrids for Synergistic Cancer Therapy in the NIR-II Window.

Metal-free layered black phosphorus (BP) nanosheets with an excellent photothermal effect and large surface areas have been widely applied in biomedicine but are easily oxidized in ambient conditions yielding insulating phosphorus oxides adsorbed on its surface. Several chemical-functionalized strategies have been explored to protect thin layers of BP; however, the performance of passivated BP often decreases significantly, falling behind the single BP due to the strong structure perturbation. Herein, we designed and constructed 0D/2D hybrid photothermal agents by assembling NIR-II-responsive carbon dots (NIR-II-CDs) on BP nanosheets.

α-Fe O Nanoparticles Decorated C@MoS Nanosheet Arrays with Expanded Spacing of (002) Plane for Ultrafast and High Li/Na-Ion Storage.

MoS nanosheets as a promising 2D nanomaterial have extensive applications in energy storage and conversion, but their electrochemical performance is still unsatisfactory as an anode for efficient Li /Na storage. In this work, the design and synthesis of vertically grown MoS nanosheet arrays, decorated with graphite carbon and Fe O nanoparticles, on flexible carbon fiber cloth (denoted as Fe O @C@MoS /CFC) is reported. When evaluated as an anode for lithium-ion batteries, the Fe O @C@MoS /CFC electrode manifests an outstanding electrochemical performance with a high discharge capacity of 1541.

Carbon dot-sensitized MoS nanosheet heterojunctions as highly efficient NIR photothermal agents for complete tumor ablation at an ultralow laser exposure.

Currently, one of the major hurdles hindering the clinical applications of photothermal therapy (PTT) and photothermal-chemo combination therapy (PCT) is the lack of highly efficient, readily derived, and irradiation-safe photothermal agents in the biologically transparent window. Herein, we report the first design and rational construction of 0D/2D/0D sandwich heterojunctions for greatly enhanced PTT and PCT performances using 0D N-doped carbon dots and 2D MoS2 nanosheets as the assembly units. The well-matching heterojunctions enabled an additional enhancement in NIR absorbance owing to the carrier injection from carbon dots to MoS2 nanosheets, and achieved a much higher photothermal conversion efficiency (78.

Boosting the energy storage densities of supercapacitors by incorporating N-doped graphene quantum dots into cubic porous carbon.

Hierarchical N-doped porous carbon has been prepared by assembling N-doped graphene quantum dots (N-GQDs) onto a carbonized metal-organic framework (cMOF-5) and used as an electrode material for supercapacitors. In this hierarchical composite structure, cMOF-5 provides an effective cubic porous framework with a large specific surface area and good electrical conductivity, while N-GQDs play an important role in enhancing the pseudocapacitive activity and improving the surface wettability of the electrode. Therefore, the N-GQD/cMOF-5 composite electrode material exhibits an outstanding specific capacitance of 780 F g-1 at 10 mV s-1 in a three-electrode system.

Hierarchical 3D All-Carbon Composite Structure Modified with N-Doped Graphene Quantum Dots for High-Performance Flexible Supercapacitors.

Flexible supercapacitors have shown enormous potential for portable electronic devices. Herein, hierarchical 3D all-carbon electrode materials are prepared by assembling N-doped graphene quantum dots (N-GQDs) on carbonized MOF materials (cZIF-8) interweaved with carbon nanotubes (CNTs) for flexible all-solid-state supercapacitors. In this ternary electrode, cZIF-8 provides a large accessible surface area, CNTs act as the electrical conductive network, and N-GQDs serve as highly pseudocapactive materials.

MoO nanosheet arrays as superior anode materials for Li- and Na-ion batteries.

MoO3 is a promising anode material for energy storage, but its electrochemical performance is still unsatisfactory. Herein, α-MoO3 nanosheets vertically grown on activated carbon fiber cloth as superior anode materials for Li- and Na-ion batteries were achieved by the method of controlled preparation. For Li-ion batteries, the resulting MoO3 array electrodes exhibit a high discharge capacity of 4.

Scalable synthesis of organic-soluble carbon quantum dots: superior optical properties in solvents, solids, and LEDs.

Carbon quantum dots (CQDs) have attracted much attention owing to their unique optical properties and a wide range of applications. The fabrication and control of CQDs with organic solubility and long-wavelength emission are still urgent issues to be addressed for their practical use in LEDs. Here, organic-soluble CQDs were produced at a high yield of ∼90% by a facile solvent engineering treatment of 1,3,6-trinitropyrene, which were simultaneously used as the nitrogen and carbon sources.

Industrial production of ultra-stable sulfonated graphene quantum dots for Golgi apparatus imaging.

The wide use of functionalized graphene quantum dots (GQDs) in stable dispersions is currently hampered by the lack of industrially scalable, low-cost, and eco-friendly methods. Herein we report the first realization of the industrial-scale (20 L) production of high-quality fluorescent GQDs via a molecular fusion route from a low-cost, active derivative of pyrene. By a wholly "green", conventional sulfonation reaction at low hydrothermal temperature, the molecular precursor is wholly converted into highly water-soluble, sulfonated GQDs without byproducts such as insoluble carbon.

Irradiated Graphene Loaded with SnO₂ Quantum Dots for Energy Storage.

Tin dioxide (SnO2) and graphene are unique strategic functional materials with widespread technological applications, particularly in the areas of solar batteries, optoelectronic devices, and solid-state gas sensors owing to advances in optical and electronic properties. Versatile strategies for microstructural evolution and related performance of SnO2 and graphene composites are of fundamental importance in the development of electrode materials. Here we report that a novel composite, SnO2 quantum dots (QDs) supported by graphene nanosheets (GNSs), has been prepared successfully by a simple hydrothermal method and electron-beam irradiation (EBI) strategies.

Theoretical study of acene-bridged dyes for dye-sensitized solar cells.

The electronic structures and absorption spectra for a series of acene-based organic dyes and the adsorption energy and optical properties for these dyes adsorbed on (TiO2)38 have been investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The effects of acene units and different substitution positions of electron donors on the optoelectronic properties of the acene-modified dyes are demonstrated. The photophysical properties of tetracene- and pentacene-based dyes are found to be tuned by changing the size of acene and the substitution position of the donor.

Fe-species-loaded mesoporous MnO2 superstructural requirements for enhanced catalysis.

In this work, a novel catalyst, Fe-species-loaded mesoporous manganese dioxide (Fe/M-MnO2) urchinlike superstructures, has been fabricated successfully in a two-step technique. First, mesoporous manganese dioxide (M-MnO2) urchinlike superstructures have been synthesized by a facile method on a soft interface between CH2Cl2 and H2O without templates. Then the M-MnO2-immobilized iron oxide catalyst was obtained through wetness impregnation and calcination.

Gram-scale synthesis of single-crystalline graphene quantum dots with superior optical properties.

Graphene quantum dots (GQDs) have various alluring properties and potential applications, but their large-scale applications are limited by current synthetic methods that commonly produce GQDs in small amounts. Moreover, GQDs usually exhibit polycrystalline or highly defective structures and thus poor optical properties. Here we report the gram-scale synthesis of single-crystalline GQDs by a facile molecular fusion route under mild and green hydrothermal conditions.

Single-particle spectroscopic measurements of fluorescent graphene quantum dots.

We have performed the first single-particle spectroscopic measurements on individual graphene quantum dots (GQDs) and revealed several intriguing fluorescent phenomena that are otherwise hidden in the optical studies of ensemble GQDs. First, despite noticeable differences in the size and the number of layers from particle to particle, all of the GQDs studied possess almost the same spectral lineshapes and peak positions. Second, GQDs with more layers are normally brighter emitters but are associated with shorter fluorescent lifetimes.

Nearly monodisperse graphene quantum dots fabricated by amine-assisted cutting and ultrafiltration.

We report a novel procedure involving polyethylenimine-assisted hydrothermal cutting and subsequent ultrafiltration for fabricating nearly monodisperse graphene quantum dots with a uniform lateral size and confined layer number. The isolated monolayer quantum dots exhibit a sharp band-edge absorption feature and strong photoluminescence (quantum yield of 21%) independent of excitation wavelength and pH. Their preliminary application in bioimaging has been demonstrated.

Assembling tin dioxide quantum dots to graphene nanosheets by a facile ultrasonic route.

Nanocomposites have significant potential in the development of advanced materials for numerous applications. Tin dioxide (SnO2) is a functional material with wide-ranging prospects because of its high electronic mobility and wide band gap. Graphene as the basic plane of graphite is a single atomic layer two-dimensional sp(2) hybridized carbon material.