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The solid-solid conversion of Li2S2 to Li2S is a crucial and rate-controlling step that provides one-half of the theoretical capacity of lithium-sulfur (Li-S) batteries. The catalysts in the Li-S batteries are often useless in the solid-solid conversion due to the poor contact interfaces between solid catalysts and insoluble solid Li2S2. Considering that ultrafine nanostructured materials have the properties of quantum size effects and unconventional reactivities, we design and synthesize for the pomegranate-like sulfur nanoclusters@nitrogen-doped carbon@nitrogen-doped carbon nanospheres (S@N-C@N-C NSs) with a seed-pulp-peel nanostructure. The ultrafine S@N-C subunits (diameter ≈5 nm) and effects of a spatial structure perfectly realize the rapid conversion of ultrafine Li2S2 to Li2S. The S@N-C@N-C seed-pulp-peel NS cathodes exhibit excellent sulfur utilization, superb rate performance (760 mAh g-1 at 10.0 C), and an ultralow capacity decay rate of about 0.016% per cycle over 1000 cycles at 4.0 C. The proposed strategy based on ultrafine nanostructured materials can also inform material engineering in related energy storage and conversion fields.

The physical confinement and chemical catalysis of lithium polysulfides (LiPSs) are effective approaches to improve the performance of lithium–sulfur (Li–S) batteries. How to effectively combine physical confinement and chemical catalysis has become the focus of research. Herein, micro–mesoporous carbon (MMC) embedded with well-dispersed ultrafine CoS2 (uCoS2) nanocrystals as an efficient sulfur host is presented. As expected, the obtained S/uCoS2@MMC cathode can achieve a synergistic effect of physical confinement and chemical catalysis of LiPSs through micro–mesoporous structures and well-dispersed uCoS2 nanocrystals. Furthermore, the MMC with a high conductive specific surface area, uniform pore size and micro–mesoporous structure can realize homogeneous loading of sulfur and physical adsorption of LiPSs. Owing to these excellent qualities, the S/uCoS2@MMC cathode delivers outstanding initial capacities up to 1227 mA h g−1 at 0.1C. More significantly, a capacity of 606 mA h g−1 is maintained after 1000 cycles at 1C (a very low capacity decay rate of only 0.032% per cycle). It can be seen that the MMC embedded with well-dispersed uCoS2 nanocrystals as the sulfur host has great application prospects in Li–S batteries.

The biodegradable nanoparticles hold tremendous potential in the field of nanomedicine because of the negligible toxicity concerns in healthy tissues/organs. We reported a simple route for the synthesis of pH-responsive biodegradable ZnO nanospheres (ZnO NSs) assembled from ultrasmall particles (sizes ranging from 4 to 8 nm, average 6 nm) with a suitable size. The nanoplatform could be responsively decomposed into small fragments under the weak acid environment to meet the requirement for pH-stimulus drug release and in favor of the biodegradation. The confocal laser scanning microscopy (CLSM) studies showed that the ZnO NSs could be efficiently internalized by cancer cells, and the loaded doxorubicin (DOX) in the NSs could be successfully released under acidic intracellular environment. Notably, the cell viabilities of DOX-loaded NSs with different sizes towards HepG-2 and HeLa cells for different incubation time were investigated, which exhibited dose-dependent and time-dependent effects. Furthermore, in vivo experiments showed that the DOX-loaded NSs displayed a significant antitumor effect (79% average inhibition rate relative to the control group) without distinct side effects. All in all the designed NSs as drug delivery systems not only achieved the excellent cancer chemotherapy but also could be rapidly decomposed or metabolized to reduce their toxicity.

In our work, we report a facile approach to fabricate well-dispersed polypyrrole@metal-organic framework (PPy@MOF) core-shell nanocomposites (NCs) with a polypyrrole (PPy) core and an MIL-100(Fe) shell. The adsorbed Fe(iii) ions on the as-fabricated PPy surface were utilized as reactive sites for further growth of the MIL-100(Fe) in the presence of trimesic acid (H3btc). The resulting NCs exhibited strong absorption in the near infrared (NIR) region and possessed an excellent photothermal efficiency of ∼40% resulting from the PPy core. The MOF structure based on Fe(iii) carboxylate materials held great ability for storage/delivery of the hydrophilic anti-cancer drug, doxorubicin (DOX). The released DOX continuously increased due to the damage of the shell at low pH values. When the DOX-loaded PPy@MIL-100(Fe) NCs were exposed to NIR irradiation, owing to the heat produced by the NCs, the local temperature increased, resulting in a faster release of DOX from the MIL-100(Fe) shell. Furthermore, PPy@MIL-100(Fe) NCs were successfully employed for dual-mode magnetic resonance imaging (MRI)/photoacoustic imaging (PAI) and synergistic chemo-photothermal therapy of cancer cells. Therefore, our work could encourage further study in the construction of a multifunctional platform using different MOF nanomaterials for cancer theranostics.

Co-delivery of two drugs with diverse physicochemical properties and specific administration order for cancer theranostics are vitally important for drug resistance conquering and side effects reducing. Consequently, we explored a unique amphiphilic PCL-AuNC/Fe(OH)3-PAA Janus nanoparticle (JNP) to simultaneously preserve the hydrophilic drug (doxorubicin) and hydrophobic drug (docetaxel) in their distinct domains. Owing to their extraordinary heterostructure and independent pH and NIR sensitive properties, the optional sequential drug release by a single inorganic JNP was realized for the first time, and the results presented the synchronous release of two drugs had 5% better therapeutic effect. In addition, the excellent computed X-ray tomography/magnetic resonance (CT/MR) imaging capabilities from AuNC and Fe(OH)3 suggested our JNPs could effectively guide the cancer therapy. Furthermore, the mice treated with dual drug loaded PCL-AuNC/Fe(OH)3-PAA JNPs under near infrared (NIR) laser irradiation showed better tumor inhibition than solo drug, cocktail and dual drug treated groups, indicating the effectivity and significance of combined cancer therapy.

Designing mixed metal oxides with uniform nanostructures as a significant electrode material in energy storage devices is a vital concern for the whole world. But achieving this goal is plagued by many problems such as tedious procedures, hard morphology control and poor conductivities. The NiCo2O4/NiFe2O4 hollow nanospheres (NSs) are prepared for the first time through a novel one-pot approach. The introduced NiFe2O4 has amazingly improved the electrochemical performance of NiCo2O4 hollow NSs in both Li-ion batteries (LIBs) and supercapacitors (SCs). And the ratio of Fe to Ni plays an important role for the improvement of electrochemical performance. The NiCo2O4/NiFe2O4 hollow NSs exhibit superior capacity/capacitance values (3795 F g−1 at a current density of 1 A g−1) and fine cycling performances (11.0% specific capacitance decay after 6000 cycles) which can be attributed to the larger specific surface area of hollow NSs and the synergistic effect of two components. This provides a feasible preview of their practical applications.

In this article, we reported a dual emissive multicolorful fluorescent-nanoprobe which was composed of gold nanocluster (BSA-Au NCs) and carbon dots (CDs) with a certain proportion, i.e. Au NCs-CDs. The dual emissive Au NCs-CDs showed pink fluorescence under UV light, and the dual emission peaks at 625 nm and 444 nm were corresponded to the existence of Hg2+ and Cr6+ respectively. The fluorescence color transformed from pink to blue when in presence of Hg2+. The blue fluorescence emission of CDs selectively quenched by Cr6+, whereas the red fluorescence of BSA-Au NCs was stable against Cr6+, which can be treated as internal reference. The difference response of the two emissions to Hg2+ and Cr6+ resulted in a distinguished fluorescent color change, which can be noticed by the naked eyes clearly. When the Hg2+ and Cr6+ were exposed to the Au NCs-CDs simultaneously, the dual-emission of the Au NCs-CDs were all reduced and exhibited the complete quenching of the pink emission. The detection limits for Hg2+ and Cr6+ were 1.85 nM and 5.34 nM, respectively. Significantly, it was successfully applied to determine the existence of Hg2+ and Cr6+ in real samples, which offered the advantages of simplicity, environmentally friendly and cost saving efficiency.

Multifunctional nanoparticles (NPs) simultaneously having functions of multimodal therapy and imaging are highly needed in biomedical applications. A unique monstera flower-like gold nanorod/polydopamine bowl (GNR/PDA bowl) with spadix-bract nanostructure was fabricated by a novel and facile approach. The possible formation mechanism of the GNR/PDA bowl spadix-bract NPs was proposed by monitoring the synthetic process. The obtained monstera flower-like GNR/PDA bowl spadix-bract NPs were further selectively functionalized with 1-dodecanethiol (DT) on GNR domains (spadix) to achieve efficient hydrophobic drug delivery capability; meanwhile, the PDA bowl (bract) can load the hydrophilic anticancer drug doxorubicin (DOX). The resultant monstera flower-like DT-GNR/PDA bowl spadix-bract NPs possess an excellent biocompatibility, high dual-drug-loading contents, excellent photothermal conversion efficiency, strong near-infrared (NIR) absorbance, effective attenuation of X-rays, and pH/NIR dual-responsive propert...

Here, we reported on a route to the facile synthesis of bimetallic silver doped copper nanoparticles (Ag-Cu NPs) by AgNO 3 and CuSO 4 in the presence of sodium borohydride and sodium citrate. The present work described the preparation of the Ag-Cu NPs with sodium citrate and the use of them in colorimetric detection of mercury (II) ions. Ag-Cu NPs with an average diameter of 9.0 ± 0.8 nm were prepared via two step reduction at room temperature. The Ag-Cu NPs were thoroughly characterized by using UV–vis spectroscopy and transmission electron microscopy (TEM) techniques. The morphology and constitution of the Ag-Cu NPs were characterized by TEM, and the valence state of Ag-Cu NPs was confirmed by the X-ray photoelectron spectroscopic (XPS) result. The synthesized Ag-Cu NPs were yellow in color due to the intense surface plasmon absorption band centered at 406 nm. This high selective sensor allowed a direct quantitative assay of mercury ions (Hg 2+ ) with a detection limited of 0.51 nM. The synthesized Ag-Cu NPs also exhibited good catalytic activity in two model reactions, the reduction of the nitrophenols and potassium ferricyanide (III) by sodium borohydride.

We herein used a low cost and facile one-step method for synthesizing fluorescent carbon-doped silicon nanoparticles (Si NPs) under mild reaction conditions. The fluorescence spectra of Si NPs showed maximum excitation and emission wavelengths at 370 nm and 450 nm, respectively. The fluorescence of the obtained Si NPs can be selectively and efficiently quenched by the Hg2+ and Ag+. The fluorescent Si NPs showed high sensitivity toward Hg2+ and Ag+ with detection limits of 2.676 μM and 0.457 μM, respectively. Moreover, the sensing ability of Si NPs for Hg2+ and Ag+ were successfully carried out in real water samples, which offered the merits of high sensitivity and high selectivity. In addition, Si NPs were also successfully employed as a promising fluorescent label for the visualization of latent fingerprints. As far as we know, this is first time that silicon nanoparticles are used to visualize latent fingerprints. The fingerprints on different surfaces (silicon wafer, patterned coin, glass sheet, copper sheet and rough plastic board) developed with this Si NPs showed very good fluorescent images with the third level under ultraviolet excitation. The method using fluorescent Si NPs as fluorescent marks provides a variety of advantages including enhanced contrast, retaining stability and non-toxicity. In addition, Si NPs showed highly non-toxic for cellular media, the efficient bioimaging of cellular imaging was enabled after incubation of HepG2 cells in the presence of Si NPs.

Blood fingerprints are an important subclass of fingerprint evidence when processing a violent crime scene. The commonly used method by the perpetrators to conceal blood stain is rinsed with water or mixed with the blood of livestock or poultry. The aim of the research presented was to overcome the above drawbacks. Herein, NaYF4: Yb, Er, Gd fluorescent upconversion nanorods were conjugated with anti-hHb (UCNRs/anti-hHb) through a coupling reaction. We then used the resultant UCNRs/anti-hHb to detect the fingerprints that inked with the blood of human, porcine and chicken. The latent human blood fingerprints showed improved contrast, whereas the blood fingerprints of porcine and chicken did not. The consequence of detection exhibited that UCNRs/anti-hHb offered the ability of specific recognition. To assess the suitability of the UCNRs/anti-hHb for potential operational use, a variety of parameters (e.g., blood concentration, substrate types and aged time) were investigated. The effectiveness of UCNRs/anti-hHb was also assessed in comparison with Acid Yellow 7 (AY7, an effective blood reagent). The results demonstrated that UCNRs/anti-hHb provided high specificity, high sensitivity, good applicability, and low background, enabling practical applications in forensic sciences.

Nitrogen-doped carbon dots (NCDs) were synthesised using a simple and straightforward solvothermal method. The resulting spherical NCDs showed stable fluorescence and a prominent fluorescence quantum yield (67%) with an average size of 3.52 nm. The fluorescence of the NCDs was quenched effectively by mercury ions (Hg2+), exhibiting a detection limit of 0.65 μM. Upon addition of a saturated solution of ethylenediaminetetraacetic acid to a dispersion of the NCDs/Hg2+ complex, the fluorescence of the NCDs underwent significant immediate recovery. Due to their favorable biocompatibility, NCDs were also demonstrated to be efficient for HeLa cell imaging. The detection of Hg2+ by NCDs could be realized in environmental water samples and living cells, with excellent results. Moreover, the as-synthesized fluorescent NCD nanopowders were used for visualizating latent fingerprints (LFPs) with significant third level detail.

Owing to their small size and unique optical properties, carbon nanomaterials have attracted considerable attention due to their promising biomedical applications. In this work, we report a silica (SiO2) protected calcination strategy to fabricate mesoporous carbon nanoframes (mCNFs) from zeolitic imidazolate framework-8 (ZIF-8) precursors. The resulting mCNFs have many merits including drug loading capability, excellent photothermal efficiency (21%), dual pH/near-infrared (NIR) responsive controlled drug release and good biocompatibility. When 5-FU-loaded mCNFs were subjected to NIR irradiation, a burst release of 5-FU occurs owing to the heat produced by the mCNFs. Furthermore, mCNFs are successfully employed for photoacoustic imaging (PAI) and synergistic chemo-photothermal cancer therapy. Taken together, mCNFs can be developed as a promising theranostic agent for cancer treatment.

A novel, facile, and one-step conventional heating method is developed to synthesize monodisperse Sn-doped Fe2O3 nanoclusters with a novel spindle-like 3D architecture. The morphology and size of the products can be controlled by adjusting the reaction time and the concentration of additive Sn ions, which are the two affecting factors for the synthesis mechanism. As a proof-of-concept demonstration of their function, our spindle-like Sn-doped Fe2O3 nanoclusters present a large capacity of 938 mA h g−1 at 0.2 C after 100 cycles as compared with bare SnO2 and Fe2O3 nanoparticles. Importantly, the capacity is about 805 mA h g−1 at 1 C with a capacity retention as high as 95% after 500 cycles when used as lithium ion battery anodes. This excellent electrochemical performance benefits from the successful doping and their 3D assembled structure, which help improve the conductivity, overcome the large volume changes and stresses during the charge–discharge reaction and finally result in the superior cycling performance and charge-rate capabilities.

The hollow nanospheres (NSs) composed of lanthanides have become a hot topic owing to their uncommon magnetic and optical properties arising from the 4f electrons. However, only a few novel methods have been developed for effectively integrating small calcium phosphate (CaP) nanoparticles and rare earth oxide drug carriers into an individual hollow mesoporous nanosphere. Herein, we report a facile, reproducible, room-temperature solution method to prepare multifunctional fluorescent hollow mesoporous Gd2O3:Eu/CaP (designated as HM-Gd2O3:Eu/CaP) NSs by using polyacrylic acid calcium (PAA-Ca) as a template. The excellent luminescent property and obvious T1-enhancement effect as well as the HM structure endow the HM-Gd2O3:Eu/CaP NSs with the capacity of simultaneous dual-modal fluorescence, magnetic resonance (MR) imaging and drug delivery. The nanocontainer-functionality of the HM-Gd2O3:Eu/CaP NSs is further validated upon filling with the anti-cancerogenic agent doxorubicin (drug-loading capacity is 749 μg mg−1). In addition, the HM-Gd2O3:Eu/CaP NSs display excellent pH-responsive and sustained drug release property. In vitro cell cytotoxicity tests verify the HM-Gd2O3:Eu/CaP NSs have good biocompatibility when the concentration ≤25 mg mL−1. Taken together, the results suggested that the HM-Gd2O3:Eu/CaP NSs can be applied as fluorescence and MR dual-modal imaging contrast agents and drug delivery vehicles.

Elaborately designed novel multifunctional therapeutic agents are highly desired for efficient cancer therapy. In this work, a new therapeutic nanoplatform based on calcium phosphate/small gold nanorod assemblies modified with methoxy-poly(ethylene glycol)-thiol (designated as PEGylated CaP/Au NR assemblies) is created via a mild, reproducible, and simple route for the first time. The obtained PEGylated CaP/Au NR assemblies possess many virtues including outstanding drug-loading capacity, excellent photothermal conversion efficiency (η, ∼38.5%), pH/near-infrared (NIR) dual-responsive release property, and good biocompatibility. After loading doxorubicin (DOX) in PEGylated CaP/Au NR assemblies, the DOX-loaded PEGylated CaP/Au NR assemblies can simultaneously supply intense heating effect and increased DOX release under 808 nm NIR laser, achieving excellent antitumor therapeutic effect in vitro and in vivo. Furthermore, the combination of DOX-loading and photothermal treatment upon PEGylated CaP/Au NR assemblies displays better therapeutic effect than single chemotherapy or photothermal therapy. Furthermore, the comprehensive methyl thiazolyl tetrazolium (MTT), hemolysis, and histological assays manifest no obvious toxicity of PEGylated CaP/Au NR assemblies. Our work elucidates the great prospect of PEGylated CaP/Au NR assemblies as a therapeutic agent for synergistic chemo-photothermal cancer therapy.

Elaborately designed novel multifunctional Janus nanoparticles (JNPs) have attracted considerable attention owing to their anisotropic surface properties and various functionalities that allow them to house several components for the detection and targeting of cancer cells. In this work, we report a novel and facile approach to synthesize Au/Fe3 O4 @C JNPs, which were further selectively functionalized with amino-poly(ethylene glycol)thiol (NH2 -PEG-SH) and folic acid (FA) on the exposed Au domains to achieve high contrast for X-ray computed tomography (CT) imaging, excellent stability, good biocompatibility, as well as cancer cell-specific targeting. Meanwhile, the other Fe3 O4 @C sides with mesoporous structure served as a drug delivery vehicle for doxorubicin (DOX), an efficient photothermal therapy (PTT) agent, and a magnetic resonance (MR) imaging contrast agent. Taking these features together, these unique multifunctional JNPs provide an intriguing nanoplatform for dual-modal CT and MR imaging-guided actively targeted chemo-photothermal synergistic cancer therapy.

A facile strategy to fabricate gold nanorod@polyacrylic acid/calcium phosphate (AuNR@PAA/CaP) yolk–shell nanoparticles (NPs) composed with a PAA/CaP shell and an AuNR yolk is reported. The as-obtained AuNR@PAA/CaP yolk–shell NPs possess ultrahigh doxorubicin (DOX) loading capability (1 mg DOX/mg NPs), superior photothermal conversion property (26%) and pH/near-infrared (NIR) dual-responsive drug delivery performance. The released DOX continuously increased due to the damage of the CaP shell at low pH values. When the DOX-loaded AuNR@PAA/CaP yolk–shell NPs were exposed to NIR irradiation, a burst-like drug release occurs owing to the heat produced by the AuNRs. Furthermore, AuNR@PAA/CaP yolk–shell NPs are successfully employed for synergic dual-mode X-ray computed tomography/photoacoustic imaging and chemo-photothermal cancer therapy. Therefore, this work brings new insights for the synthesis of multifunctional nanomaterials and extends theranostic applications. Electronic supplementary material The online version of this article (doi:10.1007/s40820-017-0155-3) contains supplementary material, which is available to authorized users.

A kind of biocompatible fluorescent nitrogen doped carbon quantum dots (NCDs) has been synthesized using uric acid as raw material through a facile, effective and green thermal treatment method in one pot. The surface morphology and optical properties of the synthesized NCDs were characterized. Without further chemical modification, the NCDs emit bright blue fluorescence with a high quantum yield of 56% due to the enhancement effect of N dopant atoms on a surface of carbon quantum dots. Owing to the strong blue fluorescence, negligible toxicity and the special response of heavy metal ions, the NCDs have been used as a fluorescence probe for sensitive and selective detection of Hg2+ and Ag+ ions with detection limit of 4.8 nM and 1 nM, respectively. Moreover, it was successfully applied to determination of Hg2+ and Ag+ in real environmental water samples, which offers the advantages of simplicity and cost efficiency.

Herein, we report a facile strategy to prepare supported lipid-bilayer-coated polyacrylic acid/calcium phosphate nanoparticles (designated as PAA/CaP@SLB NPs) as a new dual pH-responsive drug-delivery platform for cancer chemotherapy. The synthesized PAA/CaP NPs exhibited both a high payload of doxorubicin (DOX) and dual pH-responsive drug-release properties. Additionally, the coated lipid bilayer had the ability to enhance the cellular uptake of PAA/CaP NPs without affecting the pH-responsive drug release. Moreover, the blank PAA/CaP@SLB NPs exhibited excellent biocompatibility and the DOX-loaded PAA/CaP@SLB NPs markedly increased the cellular accumulation of DOX and its cytotoxic effects on HepG-2 cells. Furthermore, when used to evaluate the in vivo therapeutic efficacy in mice with the hepatocarcinoma cell line (H-22), the DOX-loaded PAA/CaP@SLB NPs exhibited superior inhibition of tumor growth compared with the free DOX group. Thus, PAA/CaP@SLB NPs are a promising drug-delivery vehicle to increase the therapeutic efficacy of anticancer drugs.

A simple, portable and recyclable method has been developed for on-site and real-time detection of Hg2+ and Pb2+ by naked eyes by using Au nanoclusters-based test paper as the fluorescent sensor. The high specificity of Hg2+ and Pb2+ to Au nanoclusters provided excellent selectivity over 15 kinds of other ions. Interestingly, an apparent fluorescent quenching of the test paper was shown when exposed to Hg2+, while a significant fluorescent enhancement was observed in the presence of Pb2+, which could be attributed to aggregation-induced fluorescence quenching and enhancement. The limit of detection for Hg2+ and Pb2+ by naked eyes was 5 μM and 50 μM, respectively. More importantly, the cyclic utilization of the test paper was achieved by immersing the test papers into ethylenediamine tetraacetic acid to recover the fluorescence of the test paper, which contributed to reducing resource consumption. Otherwise, the GSH-AuNCs test paper was competent for a practical application in environmental water samples with strong anti-interference ability.

The carbon nanostructure with heteroatom doping having well-designed porosity and a large pore volume plays a vital role in high-performance supercapacitors. Herein, we synthesize hierarchical nitrogen and sulfur-codoped micromesoporous carbon nanospheres (N,S-HPCNSs) with an ultralarge pore volume of 3.684 cm

Red phosphorus (P) has been recognized as a promising material for lithium/sodium-ion batteries (LIBs/SIBs) because of their high theoretical capacity. However, tremendous volume variation and low conductivity limit its widespread applications. Hence, we design and synthesize uniformly distributed honeycomb-like hierarchical micro-mesoporous carbon nanospheres (HHPCNSs) with ultralarge pore volume (3.258 cm3 g-1) on a large scale through a facile way. The large pore volume provides enough space for loading of P and the expansion of P, and the uniform distribution of the micro-mesopores enables the red P to load uniformly. The resulting HHPCNSs/P composite exhibits extremely high capacity (2463.8 and 2367.6 mA h g-1 at 0.1 A g-1 for LIBs and SIBs, respectively), splendid rate performance (842.2 and 831.1 mA h g-1 at 10 A g-1 for LIBs and SIBs, respectively) and superior cycling stability (1201.6 and 938.4 mA h g-1 at 2 and 5 A g-1 after 1000 cycles for LIBs and 1269.4 and 861.8 mA h g-1 at 2 and 5 A g-1 after 1000 cycles for SIBs, respectively). More importantly, when coupled with LiFePO4 and Na3V2(PO4)3 cathode, lithium/sodium-ion full batteries display high capacity and superior rate and cycling performances, revealing the practicability of the HHPCNSs/P composite. The exceptional electrochemical performance is caused by the honeycomb-like carbon network with ultralarge pore volume, uniformly distributed hierarchical micro-mesoporous nanostructure, outstanding electronic conductivity, and excellent nanostructural stability, which is much better than currently reported P/C materials for both LIBs and SIBs.

The work describes dually-emissive silicon nanoparticles (Si NPs) in aqueous dispersion with two emissions. The Si NPs respond to different solvents independently with various wavelength fluorescence emissions (red to green). The fluorescence emission wavelengths and emissive color of Si NPs can be regulated by adjustment of the solvents. Based on the effect of the solvent, a series different emission color Si NPs is obtained (Si NPs A, B, C and D), which exhibit different fluorescence emission in various solvents. Notably, the Si NP-A (dispersed in water) exhibited excellent analytical performance in sensing Cu2+ ions with amazing fluorescent response from green to brilliant blue light. The much more enhancement at 436 nm than at 500 nm was due to the changing surface chemistry of Si NPs by Cu2+, which was dependent to the concentration of Cu2+ tightly. The excellent sensitivity of Si NP-A towards Cu2+ has been testified with the detection limit as low as 0.91 μM by good linear relationship between ratio of fluorescence intensity (I436/I500) and concentration of Cu2+ (2–30 μM). The Si NP-A can be exploited as a dual-fluorescence visualization agent for latent fingerprints imaging due to the feature of dual emission. The images exhibited green emission under excited at 254 nm, and emerged green light under 365 nm, which allowed the Si NP-A applying in development of latent finger prints at complex background. These acquired fingerprints revealed the particular second-level characteristics.

The Mott-Schottky heterojunction formed at the interface of ultrafine metallic Ni and semiconducting V2 O3 nanoparticles is constructed, and the heterojunctions are "knitted" into the tulle-like monolayer nanosheets on nickel foam (NF). The greatly reduced particle sizes of both Ni and V2 O3 on the Mott-Schottky heterojunction highly enhance the number of Schottky heterojunctions per unit area of the materials. Moreover, arranging the heterojunctions into the monolayer nanosheets makes the heterojunctions repeat and expose to the electrolyte sufficiently. The Schottky heterojunctions are like countless self-powered charge transfer workstations embedded in the tulle-like monolayer nanosheets, promoting maximum of the materials to participate into the electron transfer and become catalytic active sites. In addition, the tulle-like monolayer nanosheet structure can assist in pumping liquid phase electrolyte to the surface of catalysts, owing to the capillary force. The V2 O3 /Ni/NF Mott-Schottky catalyst exhibits excellent hydrogen evolution reaction (HER) performance with a low η10 of 54 mV and needs -107 mV to get the current density of -100 mA cm-2 . Furthermore, V2 O3 /Ni/NF Schottky electrocatalyst exhibits excellent urea oxidation reaction activity: 1.40, 1.51, and 1.61 V versus reversible hydrogen electrode (RHE) voltage are required to reach a current density of 100, 500, and 1000 mA cm-2 , respectively.

Maricite NaFePO4 (NFP) as cathode for sodium-ion batteries has attracted much attention because of the high theoretical capacity (155 mA h g−1) and simple synthetic process. However, electrochemically active maricite NFP is greatly dependent on the design of the nanostructure. Highly dispersed maricite NFP nanoclusters (NFPNCs) with ultrafine NFP@C subunits (3 nm) are designed and synthesized by a facile method. The unique ultrafine NFPNCs nanostructure makes electrochemically inactive maricite NFP change to highly active amorphous phase due to the ultrafine nanosize effect. The NFPNCs based cathode displays ultrahigh capacity (149.2 mA h g−1 at 0.2C), excellent rate performance (75.7 mA h g−1 at 50C) and superior cycling performance (91.3 mA h g−1 at 10C after 5000 cycles with 95.0% retention). Even at low temperature (-10 and −20 °C), the NFPNCs still exhibit 85.5% and 75.8% capacity retention at −10 and −20 °C, respectively, in comparison to that of 25 °C. Furthermore, when coupled with hard carbon anode, the fabricated sodium-ion full batteries also exhibit high capacity, splendid cycling and rate properties. The ultrafine NFP@C subunits shorten Na+/electron diffusion pathways and provide high electrical conductivity, leading to high rate property and outstanding low temperature application.

In this work, cyclic annular Au–Cu nicotinates were synthesized through a facile one-pot method. Cupric nitrate trihydrate, hydrogen tetrachloroaurate and nicotinic acid were used as the initial reactants; nicotinic acid was found to be an excellent ligand. The Au–Cu nicotinate annularity rings were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Specifically, the shape of the assembled Au–Cu nicotinate rings can be readily controlled by changing the ratio of the reactants and the reaction time. The mechanism of growth of the Au–Cu nicotinate annular rings was also investigated; the results of the experiments indicate that the Au–Cu nicotinate annular rings were assembled from ultrathin nanosheets. The Au–Cu nicotinate rings exhibit excellent catalytic activity toward the reduction of nitrophenols (including 2-nitrophenol, 3-nitrophenol, 4-nitrophenol and 4-nitrothiophenol) by sodium borohydride in water. Experimentally, the optimized ratio of the components was found to be Au : Cu : nicotinate close to 1 : 4 : 1. Kinetic rate investigations were carried out for the Au–Cu NRs-catalyzed reactions at different cycles. Importantly for their use as catalysts, the Au–Cu nicotinate rings can be recycled and exhibit good reusability. These results indicate that Au–Cu nicotinate rings are an effective catalyst for environmental wastewater treatment.

By using a new N-donor ligand, a 3D stable pillared-layer metal–organic framework, namely [Cu4(1,4-ndc)4(L)2]·H2O·2DMF (1), has been synthesized under solvothermal conditions (1,4-H2ndc = 1,4-naphthalenedicarboxylate; L = 1-(1-(1H-imidazol-1-yl)naphthalen-4-yl)-1H-imidazole). X-ray single crystal diffraction analysis was utilized to obtain the crystal structure of 1 and 1 was further characterized by elemental analysis, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and infrared spectroscopy (IR). Based on dinuclear Cu(II) clusters as nodes, compound 1 is a 6-connected two-fold interpenetrating pcu network. Moreover, using rhodamine B (RB) and methylene blue (MB) as examples, 1 has the ability to separate dye molecules. Finally, the magnetic properties of 1 have been investigated.

Multifunctional polymer–inorganic Janus nanoparticles (JNPs) that simultaneously have therapeutic and imaging functions are highly desired in biomedical applications. Here, we fabricated spherical polydopamine/mesoporous calcium phosphate hollow JNPs (PDA/mCaP H-JNPs) via a novel and facile approach. The obtained PDA/mCaP H-JNPs were further selectively functionalized with indocyanine green (ICG) and methoxy-poly(ethylene glycol)thiol (PEG-SH) on PDA domains to achieve a superior photoacoustic (PA) imaging capability and stability, while the other mCaP sides with hollow cavities served as storage spaces and passages for the anti-cancer drug, doxorubicin (DOX). The resultant PEG–ICG–PDA/mCaP H-JNPs possess excellent biocompatibility, a competent drug loading capability, high photothermal conversion efficiency, strong near-infrared (NIR) absorbance, and pH/NIR dual-responsive properties, enabling the H-JNPs to be applied for PA imaging-guided synergistic cancer chemo-phototherapy in vitro and in vivo. Furthermore, the synthetic approach could be extended to prepare PDA/various mesoporous inorganic H-JNPs with spherical shapes for specific applications.

In this paper, the NaYF4:Yb,Er,Gd fluorescent upconversion nanorods (UCNRs) were successfully employed as a promising fluorescent label for the detection of blood fingerprints with high sensitivity, low background, high efficiency, and low toxicity on a range of substrates including non-infiltrating materials (glass, ceramic tile, aluminium foil, stainless steel sheet, coin and marble), and infiltrating materials (magazine cover and train ticket). To assess the efficiency of this approach, comparisons were performed with Acid Yellow 7 (AY7, an effective blood reagent) on above-mentioned eight substrates. The fingerprints were cut in halves and the halves treated separately with UCNRs and AY7. The results manifested that UCNRs were superior to AY7 on all test substrates. This work shows that UCNRs are a versatile fluorescent label for the detection of blood fingerprints in criminal science for individual identification.

How to construct the advanced sulfur cathode material with both high conductivity and well-defined structure is an important direction for Li–S batteries. In present study, we report a facile in situ method to prepare sulfur@nitrogen-doped carbon (S@N–C) yolk@shell nanospheres (NSs) as cathodes for Lithium–Sulfur (Li–S) batteries. The In-situ synthesis strategy eliminates the problem of diffusion of LiPSs caused by sulfur accumulated on the outer surface of N–C. Moreover, the yolk@shell structure reduces volume expansion upon lithiation through internal hollow structure and provides physical confinement and chemical adsorption of LiPSs by enclosed N–C outer shell. In addition, the electronic conductivity and reaction kinetic rate increased due to the doped nitrogen. As expected, the S@N–C NSs cathodes exhibited superior electrochemical performance for Li–S batteries (616 mAh g−1 at 1.0 C after 500 cycles).

Although lithium-sulfur (Li-S) batteries have high theoretical capacity and energy density, their practical applications have been hampered by the rapid decay of capacity caused by the shuttle effect of polysulfides. In this paper, we synthesize the MoS2/Ni3S2 yolk-shell heterostructure nanosphere (NS) and use it for the first time as the host material for Li-S batteries. The combination of yolk-shell structure and heterostructure enables MoS2/Ni3S2 NSs to have large sulfur storage space and abundant active sites, which can effectively capture polysulfides and dynamically promote the redox reaction. As the cathode of Li-S batteries, MoS2/Ni3S2@S exhibits excellent electrochemical performance and has an initial discharge capacity of 1445.4 mA h g−1 at 0.1 C. Moreover, the capacity of 739 mA h g−1 is maintained after 1000 cycles under 1 C, with an average coulomb efficiency is 97.4%. It can be seen that the multi-functional sulfur host material MoS2/Ni3S2 has great application prospects in Li-S batteries.

Co-delivery of hydrophilic/hydrophobic drugs in separate rooms and bimodal triggered drugs release from independent channels without mutual effect, coupled with multi-mode imaging are vitally significative for overcoming drug resistance and enhancing the therapeutic effects. Herein, we report the polydopamine@upconversion nanoparticle@mesoporous silica yolk-shell nanoparticles (PDA@UCNP@mSiO2 NPs) to simultaneously load the hydrophilic doxorubicin (DOX) and hydrophobic hydroxycamptothecin (HCPT) in their distinct domains for combinational chemotherapy. The oleic acid-coated UCNPs attaching onto the surface of polydopamine (PDA) exhibited the multi-mode upconversion luminescence (UCL)/computed tomography (CT)/magnetic resonance (MR) imaging and the hydrophobic environment held great ability for storage of the hydrophobic HCPT. While the mSiO2 shell was used for loading the hydrophilic DOX and ensuring the good water dispersibility of the NPs. Additionally, the NPs with near-infrared (NIR) excitation possessed an efficient photothermal efficiency of 31.1% achieving through the PDA. In a word, the resulted NPs were successfully employed for multi-mode imaging-guided synergistic dual drug chemo-photothermal therapy of hepatocellular carcinoma.

For the development of lithium-sulfur (Li-S) batteries, it is important to construct advanced host materials with large conductive, specific surface area and high activity exposed polar sites for adsorption of lithium polysulfides (LiPSs), which could promote uniform nucleation of lithium sulfide (Li2S) and liquid/solid conversion efficiency of sulfur species. Herein, we first reported the synthesis of ordered micro-mesoporous carbon (OMMC) nanospheres embedded with ultrafine iron carbide (Fe3C) nanocrystals by a facile one-step carbonizing process as effective sulfur host materials. As expected, the Fe3C/OMMC nanospheres (Fe3C/OMMC NSs) can realize homogeneous loading of sulfur, strong adsorption and catalysis of LiPSs with high efficiency, and promote uniform nucleation of Li2S through the ordered micro-mesoporous structures and ultrafine (average 5 nm) Fe3C nanocrystals. The Fe3C/OMMC-S NSs cathodes achieved excellent sulfur utilization, outstanding cyclic stability (700 mAh g−1 at 1.0 C after 1000 cycles with an ultralow capacity decay of 0.033% per cycle) and impressive rate performance (656 mAh g−1 at 5.0 C).

In this study, infrequent orange carbon nanodots (CNDs) were applied as a dual-readout probe for the effective colorimetric and fluorescent detection of 2,4,6-trinitrophenol (TNP). The orange fluorescence could be rapidly and selectively quenched by TNP, and the colorimetric response from the original pink color to blue could also be captured immediately by the naked eye. A limit of detection of 0.127 μM for TNP was estimated by the fluorescent method and 5 × 10−5 M by visualized detection. Interestingly, the fluorescence of the CNDs with TNP gradually transitioned from orange to green upon irradiation by a UV lamp, and the colorimetric response transitioned from pink to blue to colorless, which ensured effective multi-response detection of TNP. In addition, the CNDs exhibited bright fluorescence, excellent biocompatibility and low toxicity, making them high-quality fluorescent probes for cellular imaging.

A facile method to synthesize novel monodispersed SnO2@N-doped carbon hollow nanoclusters as a high-performance anode material for lithium-ion batteries was explored. The uniqueness of this structure results from the large amount of ultrafine small SnO2 nanoparticles, the hollow interior space, and the continuous N-doped carbon shells, which successfully buffer problems associated with huge volume changes and guarantee electrical connectivity. All of these features make the nanocomposite well fitted for lithium storage. As a result, the electrochemical performance of monodispersed SnO2@N-doped carbon hollow nanoclusters as an anode in lithium-ion batteries is significantly improved, as it shows high initial discharge and charge capacities of 1572 and 1003 mA h g–1, respectively. Importantly, nearly 100 % discharge/charge efficiency is maintained during 100 consecutive cycles with a specific capacity above 910 mA h g–1.

A facile, reproducible, and scalable method was explored to construct uniform Au@poly(acrylic acid) (PAA) Janus nanoparticles (JNPs). The as-prepared JNPs were used as templates to preferentially grow a mesoporous silica (mSiO2 ) shell and Au branches separately modified with methoxy-poly(ethylene glycol)-thiol (PEG) to improve their stability, and lactobionic acid (LA) for tumor-specific targeting. The obtained octopus-type PEG-Au-PAA/mSiO2 -LA Janus NPs (PEG-OJNP-LA) possess pH and NIR dual-responsive release properties. Moreover, DOX-loaded PEG-OJNP-LA, upon 808 nm NIR light irradiation, exhibit obviously higher toxicity at the cellular and animal levels compared with chemotherapy or photothermal therapy alone, indicating the PEG-OJNP-LA could be utilized as a multifunctional nanoplatform for in vitro and in vivo actively-targeted and chemo-photothermal cancer therapy.

A simple, novel, and reproducible synthetic strategy was developed to fabricate multifunctional Fe3O4@carbon/zinc phosphate core–shell nanoparticles (Fe3O4@C/ZnP NPs), which were employed as pH/near infrared (NIR)-responsive drug carriers for simultaneous magnetic resonance imaging (MRI) and synergistic chemo-photothermal cancer therapy in vitro.

A new microporous robust zirconium metal–organic framework (Zr-MOF), NNU-28, has been synthesized and employed as a visible-light photocatalyst for carbon dioxide (CO2) reduction to produce formate. NNU-28 is constructed by using a visible light responsive organic ligand derived from an anthracene group. Studies reveal that the as-prepared Zr-MOF shows desirable characteristics including excellent chemical and thermal stability, high CO2 uptake, broad-band visible light absorption and efficient photoinduced charge generation. Remarkably, NNU-28 is highly efficient for visible-light-driven CO2 reduction with a formate formation rate of 183.3 μmol h−1 mmolMOF−1, which is among the highest performances of Zr-MOFs. Both photocatalytic experiments and electron paramagnetic resonance (EPR) studies reveal that both the inorganic building unit Zr6 oxo cluster and the anthracene-based ligand contribute to the highly efficient photocatalysis of CO2 reduction. The dual photocatalytic routes are demonstrated here to be more efficient for visible-light-driven CO2 photoreduction than that typically relying on a ligand-to-metal charge transfer process, illustrating a new strategy to design and synthesize novel visible-light photocatalysts for CO2 reduction with high efficiency.

Visible-light-induced controlled/living radical polymerization (C/LRP) mediated by photoactive zirconium metal–organic framework (Zr–MOF) NNU-28 has been explored. The photopolymerization is carried out at room temperature under 520 nm monochromatic light. The results show that anthracene-based NNU-28 is a promising heterogeneous sensitizer to initiate the photopolymerization where the robust Zr–MOF exhibits enhanced visible light absorption and characteristics of photoinduced charge generation. The NNU-28 mediated CRP relies on the in situ photoreduction of a Cu(II) complex deactivator to Cu(I) complex activator through an electron transfer process. The photopolymerization of methacrylates shows typical characteristics of controlled radical polymerization, where the as-prepared polymers have controlled molecular weights, narrow molecular weight distribution and high retention of chain-end groups. Besides, the NNU-28 mediated photopolymerization can be temporally and spatially controlled by light. The visible-light-induced polymerization investigated here suggests the promising application of photoactive MOFs for well-designed polymer synthesis.

A series of three-dimensional (3D) copper nicotinate hollow microstructures were fabricated by a one step method. The shape of the copper nicotinate hollow microstructures evolved from a hexagon, to an octagon and to a tetragonum, depending on the setting time and concentrations of the reactants. The 3D copper nicotinate hollow microstructures were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR) and scanning electron microscopy (SEM). The mechanism of the growth of the copper nicotinate hollow microstructures has also been investigated, which indicated that 3D copper nicotinate hollow microstructures were assembled by ultrathin copper nicotinate nano-sheets. The catalytic activities of the as-obtained copper nicotinate hollow microstructures for the reduction of 4-nitrophenol by sodium borohydride were examined. The catalytic activity of copper nicotinate hollow microstructures was greatly improved due to the hollow structure.

We report a facile and simple hydrogen reduction method to fabricate PEGylated branched gold (Au)–iron oxide (Fe3O4) Janus nanoparticles (JNPs). Note that the hydrogen induces the formation of Fe3O4 during the synthesis process. Due to the strong absorption in the near-infrared range, branched Au–Fe3O4 JNPs showed a significant photothermal effect with a 40 % calculated photothermal transduction efficiency under a laser irradiation of 808 nm in vitro. Owing to their excellent optical and magnetic properties, branched Au–Fe3O4 JNPs were demonstrated to be advantageous agents for triple-modal magnetic resonance imaging (MRI)/photoacoustic imaging (PAI)/computed tomography (CT) in vitro. Therefore, the synthetic approach could be extended to prepare Au–metallic oxide JNPs for specific applications.

A novel, facile and reproducible method was explored to construct uniform folic acid-Au@poly(acrylic acid)/mesoporous calcium phosphate Janus nanoparticles (FA-Au@PAA/mCaP JNPs), which act as an efficient nanoplatform for X-ray computed tomography (CT) imaging and active-targeted chemotherapy in vitro.

Binary transition metal oxides are recently gaining prominence as promising anode materials for next-generation Li-ion batteries (LIBs), owing to its intrinsic merits. Herein, in our work, highly dispersible ZnFe2O4 hollow nanospheres (denoted as ZFO-HNSs) assembled by ultra-small ZFO subunits (average diameter ∼15 nm) have been prepared via one-pot and cost-effective method on a large scale. Surprisingly, the results of electrochemical test show that the ZFO-HNSs possess an excellent super-long cycle performance (1044 and 900 mA h g−1 at 500 and 1000 mA g−1 over 400 cycles, respectively), which break the previous documentary records among the as reported pure ZFO anode materials, excellent electrochemical performance benefits from the unique ZFO-HNSs are assembled by ultra-small ZFO subunits, thus providing a preview of their practical applications in LIBs. More meaningfully, other binary transition metal oxides (such as ZnCo2O4, ZnMn2O4 and CoFe2O4) can be further fabricated by our strategy, which maybe promote the further application of them in adsorption, photocatalysis, supercapacitor and microwave absorption fields.

Elaborate design of multifunctional Janus nanoparticles (JNPs) with asymmetric compositions and independent functions has drawn extensive attention in biological fields. Here, a mild synthesis strategy is first explored for the preparation of spherical zeolitic imidazolate framework-8/polydopamine JNPs with hollow structure (H-ZIF-8/PDA JNPs). The resultant H-ZIF-8/PDA JNPs are further selectively functionalized on PDA sides with heptakis-(6-mercapto-6-deoxy)-β-cyclodextrin (CDs) to gain the capability of loading hydrophobic drug (H-ZIF-8/PDA-CD JNPs). Meanwhile, the ZIF-8 domains with hollow cavities can serve as reservoirs for loading hydrophilic drug molecules. Moreover, the pH-sensitive ZIF-8 and the strong near-infrared (NIR) absorption of PDA make the H-ZIF-8/PDA JNPs possess the conversion capacity from laser energy to heat and pH/NIR dual-responsive drug release behaviors. Besides, the Cell Counting Kit-8 (CCK-8), hemolysis and histological assays manifest the excellent biocompatibility of H-ZIF-8/PDA-CD JNPs. The therapeutic results in vitro and in vivo both reveal that the hydrophobic/hydrophilic drugs co-loaded H-ZIF-8/PDA-CD JNPs irradiated by 808 nm laser groups show the best therapeutic efficiency. Taken together, the H-ZIF-8/PDA-CD JNPs are capable of serving as promising platform for cancer treatment through collaborative photothermal and dual-drug chemical therapy.

A facile one-pot synthetic strategy was explored to synthesize carbon/calcium phosphate/Fe3O4 composite nanoparticles (carbon/CaP/Fe3O4 composite NPs). Taking advantage of the unique structure including mesoporous, small CaP and Fe3O4 subunits homogeneously distributed in a carbon matrix, carbon/CaP/Fe3O4 NPs integrate high drug loading, pH/NIR-sensitive, photothermal and magnetic properties into one nanoplatform for cancer theranostics.

Correction for ‘Facile synthesis of orange emissive carbon dots and their application for mercury ion detection and fast fingerprint development’ by Mingyu Tang et al., Anal. Methods, 2019, DOI: 10.1039/c9ay00178f.

Monodispersed and uniform Au@mesoporous SnO2 yolk–shell nanoparticles (Au@mSnO2 yolk–shell NPs) composed of the moveable Au NP cores and mSnO2 shells have been successfully fabricated via a facile and reproducible approach. The outside mSnO2 shells of Au@mSnO2 yolk–shell NPs not only prevent Au NPs from aggregating and corroding by the reaction solution but also allow the Au NPs to contact with reactant molecules easily through the mesoporous channels. The obtained Au@mSnO2 yolk–shell NPs are characterized by means of transmission electron microscope, scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectrum, and UV–vis absorption spectroscopy. The synthesized materials exhibit excellent catalytic performance and high stability towards the reduction of 4-nitrophenol with NaBH4 as a reducing agent, which may be ascribed to their high specific surface area and unique mesoporous structure. Moreover, the synthetic strategy reported in this paper can be extended to fabricate a series of multifunctional noble metal@metal oxide yolk–shell nanocomposite materials with unique properties for various applications.