Improvement of synergistic effect photocatalytic/peroxymonosulfate activation for degradation of amoxicillin using carbon dots anchored on rod-like CoFe_(2)O_(4)

β-lactam antibiotics in aquatic environment have severely damaged ecological stability and caused a series of environmental pollution problems to be solved urgently.Herein,a novel composite photocatalyst prepared by loading carbon dots(CDs)onto rod-like CoFe_(2)O_(4)(CFO),which can effectively degrade amoxicillin(AMX)by photocata lytic/peroxy mono sulfate(PMS)activation under visible light irradiation.The degradation results exhibits that the optimal degradation efficiency with 97.5%within 80 min is achievd by the CDs-CFO-5 composite.Such enhanced activity is ascribed to the introduction of CDs that effectively improves the separation efficiency of photogenerated electron pairs and creates new active sites as electron bridges that improve the photocata lytic performance.More importantly,a strong synergistic between CDs and photo-induced electrons generated from CFO can further activiate PMS to provide more SO4-·and·OH radicals for boosting the degradation ability towards AMX.The present study aims to elucidate positive role of CDs in photocata lytic/peroxy monosulfate activation during the degradation reaction.

Study of Photocatalytic Activity of a Nanostructured Composite of ZnS and Carbon Dots

Environmental pollution jeopardizes our existence. For this purpose, research is moving more and more towards the search for economic means and green chemistry to curb this phenomenon. In this context, the photocatalytic activity of zinc sulfide nanoparticles (ZnS NPs) and nanostructured composite ZnS/carbon dots (ZnS/CDs) was evaluated after their synthesis. The results of X-ray diffraction (XRD) analysis indicate that the crystal structure of ZnS/CDs is identical to that of the cubic phase structure of ZnS, revealing that the cubic phase structure of ZnS was not altered in the presence of CDs. Indeed, there is no additional peak in the crystal structure of ZnS/CDs, revealing that the crystalline structure of ZnS is not responsible for the difference in photocatalytic activity between ZnS/CDs and ZnS NPs. Moreover, analysis performed by transmission electron microscopy (TEM) shows aggregation of the synthesized ZnS and ZnS/CDs nanoparticles with an average size estimated around 10 nm and 12 nm, respectively. In addition, the reflectance study in the visible range shows a reduction in the sunlight reflection intensity using ZnS/CDs compared to the capability of ZnS NPs. Photocatalytic degradation tests reveal that ZnS/CDs have the best methylene blue (MB) degradation rate. Indeed, under the optimal conditions, the photocatalytic activity can reach 100% efficiency within 100 min and 240 min of sunlight exposure for the degradation of 7.5 mg/L MB using ZnS/CDs and ZnS, respectively. This improvement in photocatalytic activity of ZnS/CDs may be due to the presence of CDs which can permit to undergo a reduction of reflection properties of ZnS NPs in the visible range. These results show that CDs can play a key role in enhancing the photocatalytic activity of ZnS, and suggest that ZnS/CDs could be used as eco-friendly composite materials for the degradation of organic pollutants of similar structures in the aquatic environment under solar irradiation.

Synthesis of carbon dots with predictable photoluminescence by the aid of machine learning

Carbon dots(CDs)have wide application potentials in optoelectronic devices,biology,medicine,chemical sensors,and quantum techniques due to their excellent fluorescent properties.However,synthesis of CDs with controllable spectrum is challenging because of the diversity of the CD components and structures.In this report,machine learning(ML)algorithms were applied to help the synthesis of CDs with predictable photoluminescence(PL)under the excitation wavelengths of 365 and 532 nm.The combination of precursors was used as the variable.The PL peaks of the strongest intensity(λ_(s))and the longest wavelength(λ_(l))were used as target functions.Among six investigated ML models,the random forest(RF)model showed outstanding)performance in the prediction of the PL peaks.

Carbon dots with two-photon fluorescence imaging for efficient synergistic trimodal therapy

Applying the fluorescent carbon dots as smart materials in anticancer therapy is of great interest.However,carbon dots for multimodal synergistic anticancer therapy,especially for the triple modality,is rarely reported.Herein,we successfully synthesized OCDs by citric acid and(1R,2S)-2-amino-1,2-diphenylethan-1-ol,which show aggregation-induced emission property and two-photon fluorescence imaging.Meanwhile,OCDs are ideal photosensitizers for photothermal therapy under 808 nm and TypeⅠphotodynamic therapy with white light.Hydroxyl radicals,generated by TypeⅠphotodynamic therapy based on OCDs can transform protumoral M2 macrophages into antitumoral M1 macrophages,which exhibited immunotherapy ability.The synergism trimodal of OCDs results in potent anticancer efficacy,showing great potential in cancer therapy.

Red carbon dots as label-free two-photon fluorescent nanoprobes for imaging of formaldehyde in living cells and zebrafishes

Direct,in situ selective detection of intracellular formaldehyde(FA)is of great significance for understanding its function in FA-related diseases.Herein,red carbon dots(RCD)are reported as label-free two-photon fluorescent nanoprobes for detecting and imaging of FA.Upon addition of FA,the-NH2 groups of RCD could quickly and specially react with aldehydes to form Schiff base and then the strong fluorescence of RCD with blue-shift emission is recovery due to the destruction of the hydrogen bond interaction between RCD and water.In addition,the nanoprobes exhibit outsta nding photo stability,rapid response(<1 min),high sensitivity(~9.9μmol/L)and excellent selectivity toward FA over other aldehyde group compounds.Notably,owing to the good cell-membrane permeability and biocompatibility,as well as the large two-photon absorption cross-section,the as-prepared RCD can be used as label-free nanoprobes for selectively detecting and imaging FA in living cells and zebrafishes through one-photon and two-photon excitation.Moreover,RCD could stain the tissue of zebrafishes at depths interval of up to 240μm under two-photon excitation.This research implied that RCD are promising tools for directly and in situ imaging FA in vivo,thus providing critical insights into FA-related pathophysiological processes.

Tribological performance of various metal-doped carbon dots as water-based lubricant additives and their potential application as additives of poly(ethylene glycol)

Advances in nano-lubricant additives are vital to the pursuit of energy efficiency and sustainable development.Carbon dots(CDs)have been widely investigated in the domain of lubricant additives owing to their extraordinary tribological properties,in particular,their friction-reducing and anti-wear properties.Metal-doped CDs are a new type of CDs,and their friction-reducing and anti-wear properties are attracting increasing attention.Therefore,a series of CDs doped with various divalent metal ions have been successfully synthesized via one-pot pyrolysis.The tribological properties of the synthesized CDs as water-based lubricant additives are in the following order:Zn-CDs>Cu-CDs>>Mg-CDs>Fe-CDs>U-CDs.Specifically,adding 1.0 wt%of Zn-CDs into water-based lubricant results in 62.5%friction and 81.8%wear reduction.Meanwhile,the load-carrying capacity of the water-based lubricant increases from 120 N to at least 500 N.Zn-CDs as an additive have long service life.Additionally,anion-tuned Zn-CDs fabricated via anion exchange exhibit promise as lubricant additives for poly(ethylene glycol).Based on the results of wear scar surface analyses,it is discovered that tribochemical films,primarily composed of iron oxides,nitrides,metal carbonates,zinc oxides,zinc carbonates,organic compounds,and embedded carbon cores,formed on the rubbing surfaces with a thickness of approximately 270 nm when Zn-CDs are used as additives.This film combined with the“ball-bearing”and third-particle effects of Zn-CDs contributed to excellent lubrication performance.

Polyetherimide functionalized carbon dots with enhanced red emission in aqueous solution for bioimaging

Red emissive carbon dots(CDs)are highly desired for biological applications.However,serious luminescence quenching of red emissive CDs in aqueous solution greatly hinders their application in high performance biological imaging.Herein,we reported a facile strategy to realize enhanced red emission of CDs in aqueous solution by surface modification with polyetherimide(PEI)via microwave heating method.High photoluminescence quantum yield(PLQY)of 25%was realized from the PEI functionalized CDs(CDs@PEI)in aqueous solution.The proposed PEI functionalization strategy not only protects the red emission against water molecules quenching,but also reverses the surface charges from negativity to positivity to promote cellular uptake of CDs,leading to clear cell imaging in red fluorescence region.More important,CDs@PEI exhibits much better photostability than commercial red emissive dye(MitoT racker red)in cell fluorescent imaging.Potential application of CDs@PEI on fast staining of cells for clonogenic assay has also been demonstrated.

The utilization of carbon-based nanomaterials in bone tissue regeneration and engineering:Respective featured applications and future prospects

In recent years,with advancements in bone tissue regeneration and engineering technologies,carbon-based nanomaterials(CNMs)have progressively demonstrated advantages in the therapies of critical bone defects and related diseases that conventional substances fail to develop,such as excellent mechanical properties,large specific surface,tunable surface characteristics,and superior biocompatibility.More importantly,carbon-based nanomaterials with efficient cell proliferation and osteogenic differentiation could have a significant impact on bone tissue regeneration.In this paper,we have reviewed the characteristic applications of extraordinary types of carbon-based nanomaterials(fullerene,carbon dots,carbon nanotubes,as well as graphene and its derivatives)in bone tissue regeneration and engineering based on their structural properties,with a view to presenting their unique advantages,applications,and current directions of development as specifically and comprehensively as possible.