The development of sensitive and reliable methods to monitor the presence of mercuric ions in cells and organisms is of great importance to biological research and biomedical applications. In this work, we propose a strategy to construct a solar-driven nanoprobe using a 3D Au@MoS2 heterostructure as a photocatalyst and rhodamine B (RB) as a fluorescent and color change reporter molecule for monitoring Hg2+ in living cells and animals. The sensing mechanism is based on the photoinduced electron formation of gold amalgam in the 3D Au@MoS2 heterostructure under visible light illumination. This formation is able to remarkably inhibit the photocatalytic activity of the heterostructure toward RB decomposition. As a result, “OFF–ON” fluorescence and color change are produced. Such characteristics enable this new sensing platform to sensitively and selectively detect Hg2+ in water by fluorescence and colorimetric methods. The detection limits of the fluorescence assay and colorimetric assay are 0.22 and 0.038 nM for Hg2+, respectively; these values are well below the acceptable limits in drinking water standards (10 nM). For the first time, such photocatalysis-based sensing platform is successfully used to monitor Hg2+ in live cells and mice. Our work therefore opens a promising photocatalysis-based analysis methodology for highly sensitive and selective in vivo Hg2+ bioimaging studies.

Portable, low-cost, and quantitative detection of cancer cells at home and in the field has the potential to revolutionize medical diagnostics. We first report the design and synthesis of highly efficient folic-acid-conjugated hydrogen-generation tube-in-tube CuO/Co3O4 heterojunction nanofibers for highly sensitive and rapid recognition of cancer cells through a pressure signal under visible-light irradiation. The resultant nanofibers can dramatically enhance the hydrogen-generation activity of ammonia borane under visible-light irradiation. Such hydrogen-generation reaction can translate a molecular recognition event between folic acid and folate receptor to measurable pressure signal readout through a low-cost and portable pressure meter for target cancer cell detection. Limits of detection (LODs) down to 50 cells mL–1 in only 15 min can be achieved. This result is superior to those of the other reported methods, indicating the superiority of the new pressure-based sensor in terms of sensitivity. The present study establishes the pressure meter as a useful tool for early clinical point-of-care cancer diagnosis.

We successfully synthesized blue, green, and red CsPbX3 QDs-codoped flexible films using a one-step electrospun strategy, followed by coating a strongly hydrophobic silicone resin on the surface of the films. The codoped flexible light-emitting films are resistant to water, thereby preventing anion exchange and significantly prolonging the lifetime of light emitters under ambient air conditions.

The assembly of aligned porous materials from simple building blocks is of widespread interest for engineering materials with enhanced and synergistic properties. To date, however, how to develop 3D heterojunction aerogels with aligned porosity based on 2D semiconductor materials and 1D conducting polymers for solar energy conversion in the visible and near-infrared (NIR) light region remains a significant challenge. Here a new class of gram-scale 3D aligned heterojunction aerogels of polypyrrole (PPy)/C3N4 nanosheets (NSs) were designed and synthesized by directional freezing of polypyrrole (PPy)/polyvinyl alcohol (PVA) and C3N4 NS aqueous suspension. The synthesis of aligned C3N4–PPy heterojunction aerogels can be achieved on a large scale. The formed aerogel expresses stable and uniform dispersion of the two building blocks, long-range channel aligned structures along the whole monolithic sample, and additional special complementary optical properties between PPy and C3N4 NSs. Based on the above unique structure and optical properties, this novel metal-free heterojunction aerogel exhibits excellent photocatalytic activity and long-term stability for direct arylation of heteroaromatics under visible and near infrared (NIR) light irradiation at room temperature, far exceeding those of the single- and two-component systems. Our work therefore not only provides a new approach to obtain aligned heterojunction aerogels based on metal free semiconductors but also paves a way to develop gram-scale aerogels as a new type of highly efficient visible and NIR light induced heterogeneous photocatalyst.

Visible light mediated photoredox arylations can proceed under very mild conditions and have therefore become attractive. Nowadays, various metal nanomaterials and metal complexes have been developed as photocatalysts for direct arylation of heteroaromatics. These photocatalysts, however, still suffer from corrosion, high cost, aggregation or poor stability. We report the design and fabrication of a g-C3N4/rGO nanocomposite and demonstrate its excellent activity, high apparent quantum efficiency, and recyclability to catalyze the metal free direct arylation of heteroaromatics under visible light at room temperature. Moreover, the g-C3N4/rGO catalyst can be reused more than five times without significant loss of activity, confirming this catalyst's excellent stability. The present strategy to fabricate a metal-free g-C3N4/rGO nanocomposite for direct C–H arylation open a new avenue towards replacing metal-based catalysts in fine organic synthesis.

Nowadays, the development of a multifunction system for the simultaneous multiple signal amplification detection and fast removal of Hg2+ remains a major challenge. Herein, we for the first time used gold nanoparticles (Au NPs) and the corresponding filter membrane as chemosensors and adsorbents for dual signal amplification detection and fast removal of Hg2+. Such a system was based on the formation of gold amalgam and a gold amalgam-based reaction between rhodamine B (RhB) and NaBH4 with fluorescence and colorimetric sensing functions. When the gold amalgam catalyzes the reduction of RhB, the red color and orange fluorescence of RhB gradually changed to colorless by switching the amount of Hg2+ deposited on 13 nm Au NPs. The detection limit of the fluorescence assay and colorimetric assay is 1.16 nM and 2.54 nM for Hg2+, respectively. Interestingly, the color and fluorescence of RhB could be recovered when the above colorless reaction solution was exposed to air for about 2 hours. Taking advantage of the above optical phenomenon, a recyclable paper-based sensor has been developed by immobilizing the Au NPs and RhB dye on filter paper and has been successfully used for detection of Hg2+ in real water samples. In addition, the filter membrane immobilized Au NPs could allow fast removal of mercury ions in Yellow river water and tap water with the removal efficiency close to 99%.

A three-dimensional (3D) Pd-reduced graphene oxide framework (Pd-rGOF) with hierarchical macro- and mesoporous structures has been developed via covalence- and coordination-assisted self-assembly approach. In this facile fabrication process, GO was first cross-linked with triethylene tetramine (TETA) to form 3D GOF, in which well-dispersed and ultrasmall Pd nanoparticles (NPs) in situ grew and embedded the framework. The obtained nanopores, 3D Pd-rGOF, can act as nanoreactors to help the reaction substrates thoroughly contact with the surface of Pd NPs, thereby exhibiting high activity and selectivity toward the Tsuji–Trost reaction in water, with 99% conversion and selectivity for most substrates. Moreover, the 3D Pd-rGOF catalyst can be reused more than ten times without significant loss of activity, rendering this catalyst long-term stability. The abovementioned observations make the rGOF a universal platform to coordinate other noble metal ions (NM) to construct desired NM-rGOF nanocatalysts with improved activity, selectivity, and durability that can be used in a broad range of practical applications.

The three-dimensional porous Fe3O4@Cu2−xS–MoS2 framework is reported for the first time. The as-prepared 3D framework exhibits good structural stability, high surface area, enhanced adsorption capacity to substrates, and strong absorption in the NIR range. As a result, such hybrid frameworks exhibit excellent NIR-light photocatalytic activity and stable cycling for the direct arylation of heteroaromatics at room temperature.

Precise detection and effectively eliminating mercury pollution in aqueous solutions remains an onerous task for protecting the public health and environment. In this paper, porous MoS2 composite aerogel-supported Au nanoparticles with strong mercury affinity have been fabricated to deal with this problem. Such composite aerogels are fabricated using graphene oxide (GO)-doped MoS2 sheets as the feedstock by hydrothermal assembly and then the Au and Fe3O4 nanoparticles (NPs) embed between the GO-doped MoS2 sheets through coordination. The resultant porous Au/Fe3O4/MoS2CAs aerogel not only can sensitively detect mercury(II) in aqueous solution by a colorimetric method with a low detection limit (3.279 nM) but also can exhibit a super mercury adsorption capacity (∼1527 mg g–1) and fast desorption ability. After magnetic separation, the Hg2+ levels decreased from 10 ppm to 0.11 ppb within a few minutes, which is far below 2 ppb. In addition, Au/Fe3O4/MoS2CAs could be successively recycled more than 10 times with high removal efficiency (>95%). The excellent performance of the composition aerogel profits from its 3D interconnected macroporous framework as well as strong coupling between Au nanoparticles and MoS2 nanosheets, rendering it a potential detection and adsorbent material for mercury(II) from contaminated water for environmental remediation.Keywords: Detection; Mercury(II); MoS2 composition aerogel; Removal; Three-dimensional

•Pd/Fe3O4-PEI-RGO was synthesized by dispersion of Pd NPs and Fe3O4 NPs on GO sheets.•Pd/Fe3O4-PEI-RGO provides a sensing platform for the colorimetric detection of H2O2.•Pd/Fe3O4-PEI-RGO has the advantages of facile preservation and rapid separation.•Pd/Fe3O4-PEI-RGO has the enhanced peroxidase catalytic activity.Herein Pd/Fe3O4-PEI-RGO nanohybrid was synthesized by dispersion of Pd NPs and Fe3O4 NPs on PEI modified graphene oxide sheets. This nanohybrid was found to possess superior peroxidase-like activity, and could efficiently oxidize 3,3′,5,5′-Tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to produce a color reaction. Therefore, this provides a sensing platform for the colorimetric detection of H2O2 in solution. The linear range for H2O2 was from 0.5 to 150 μM and the limit of detection was as low as 0.1 μM. Moreover, the nanohybrids have the advantages of facile preservation and rapid separation. More importantly, comparing with the other catalysts (PEI-RGO, Fe3O4-PEI-RGO and Pd-PEI-RGO), this nanohybrid exhibits the enhanced peroxidase catalytic activity. Thus, it is expected that this nanohybrid could conveniently and efficiently detect H2O2 in the pharmaceutical, environmental and industrial fields.We reported as-synthesized Pd/Fe3O4-PEI-RGO nanohybirds as enhanced peroxidase mimetics for the colorimetric detection of H2O2 in solution.

Currently tremendous efforts have been made to fabricate different noble metal nanoparticles (NPs) encapsulated in porous materials. Herein we present a general strategy for the preparation of coupled Fe3O4 and Au NPs into carbon nanospheres by employing diethylenetriamine as the coupling linker. Transmission electron microscopy images show that Au NPs were embedded into magnetic carbon nanospheres, and the mean particle size of Au is around 2.6 nm. The nanohybrids were used as catalysts to remove methylene blue from wastewater in the presence of NaBH4. The results indicated that this catalyst exhibited superior catalytic activity toward methylene blue with a high degradation efficiency above 99% in aqueous solution, which is attributed to the high dispersity of the Au NPs into carbon nanospheres. Moreover, this catalyst showed good selectivity toward methylene blue in the presence of other pollutants. More importantly, the catalyst could be conveniently separated and recycled from the reaction mixtures using an external magnetic field, and the catalytic activity was still retained even over nine cycles. This work indicates that the nanohybrid could be a promising catalyst for the highly efficient and selective degradation of methylene blue from its dye mixtures.

Fluorescent chemosensors for detecting single anions have been largely synthesized. However, the simultaneous detection and degradation of multiple anions remain a major challenge. Herein we report the synthesis of a white emission nanoprobe on the basis of a Coumarin-Rhodamine CR1-Eu complex coordinated to dipicolinic acid (dpa)-PEG-Fe3O4 nanoparticles for the selective detection of ClO− and SCN− ions on controlling by a logic gate. The obtained nanoprobe exhibits three individual primary colors (blue, green, and red) as well as white emission at different excitation energies. Interestingly, this nanoprobe shows a marked rose red to violet emission color change in response to ClO−, a reversible violet to rose red emission color change in response to SCN−, and high ClO− and SCN− selectivity and sensitivity with a detection limit of 0.037 and 0.250 nM, respectively. Furthermore, the SCN− and ClO− can degrade simultaneously through the redox reaction between ClO− and SCN−.

Rapid and simple molecular recognition based techniques for the identification of the subtypes of cancer cells are essential in molecular medicine. However, improving the sensitivity and accuracy of the early diagnosis of this disease remains a major challenge. Herein, we develop a novel approach for the in situ growth of palladium nanoparticles in magnetic carbon nanocages (PdNPs/MCNCs). The confined Pd NPs, which have excellent dispersion in magnetic carbon nanocages, show superior catalytic performance for the cleavage reaction of N-butyl-4-NHAlloc-1,8-naphthalimide (NNPH), thereby producing significant changes in both color (from colorless to jade-green) and fluorescence (from blue to green) through the ICT process. Based on the abovementioned results, a novel sensing platform utilizing the PdNPs/MCNC nanocatalyst as an artificial enzyme and NNPH as a fluorescent and color change reporter molecule for the multicolor imaging and colorimetric detection of cancer cells was developed. We envision that this nanomaterial can be used as a power tool for a wide range of potential applications in biotechnology and medicine.

We have developed an efficient strategy for synthesizing a strongly coupled Au/Fe3O4/GO hybrid material to improve the catalytic activity, stability, and separation capability of Au nanoparticles (NPs) and Hg2+. The hybrid material can be synthesized by the direct anchoring of Au and Fe3O4 NPs on the functional groups of GO. This approach affords strong chemical attachments between the NPs and GO, allowing this hybrid material to ultrasensitively detect Hg2+ in aqueous solutions with a detection limit as low as 0.15 nM. In addition, the deposition of Hg0 on the surface of Au/Fe3O4/GO could be quickly (within 30 min) and efficiently (>99% elimination efficiency) removed by the simple application of an external magnetic field and then Au/Fe3O4/GO could be subsequently reused at least 15 times, with the elimination efficiency remaining high (>96%).

A novel atom-scale interfacial coordination assisted synthesis method for the textural engineering of three-dimensional (3D) Fe3O4–graphene oxide frameworks with hierarchical macro- and meso-porous structures is developed.

A new three-dimensional (3D) mesoporous hybrid framework was synthesized by coordinated layer-by-layer assembly between nanosheets of reduced graphene oxide and Fe3O4@Cu2O. This 3D mesoporous framework shows an excellent catalytic performance with a remarkable activity, selectivity (>99%), and strong durability in the synthesis of quinoxalines.

A high-performance imaging probe with NIR luminescence and synergistically enhanced T1−T2 relaxivity was synthesized. This nanoprobe exhibits a relatively high tumor-targeting efficacy and enables NIR optical and T1-/T2-weighted MR imaging of hepatic tumor cells in vivo.

The combination of different fluorescent species into one nanostructure to develop fluorescent nanoparticles with multiple emission signatures by a single wavelength excitation has become a very popular research area in the field of multiplex bioanalysis, diagnostics, and multicolor imaging. However, these novel hybrids must be elaborately designed to ensure that the unique properties of each component are conveyed, i.e., fluorescent species and nanoparticles, and are maximized without serious interactions with each other. Herein, a first triple-fluorescence dumbbell nanoprobe with large Stokes shift based on incorporating fluorescein isothiocyanate (FITC) and lanthanide complexes onto Au–Fe3O4 NPs was synthesized. This hybrid displays well-resolved triple fluorescence emission, with FITC at 515 nm, Tb(III) complex at 545 nm, and Eu(III) complex at 616 nm under a single-excitation wavelength and is used for highly selective and sensitive colorimetric detection of Cu2+ with a detection limit of 30 nM. Under different Cu2+ concentrations, this hybrid exhibited distinguishable multiple colors under UV light, and the color could change in the presence of different concentrations of Cu2+. This sensor for ratio/multianalyte microscopic imaging of Cu2+ in HeLa cells and BHK cells was also demonstrated. Target molecules, such as folic acid, can be covalently attached to the fluorescent nanoparticle surface to serve as an effective probe for simultaneous multicolor imaging folate receptor-overexpressing HeLa cell lines in vitro.

The catalytic activity of nanocrystal catalysts depends strongly on their chemical composition, size, and shape. Herein, we report four different sizes and shapes of MnFe2O4 nanoparticles (NPs) prepared by a hydrothermal procedure. In addition, the size- and shape-dependent peroxidase-like activity of these NPs was first explored using 3,3′,5,5′-tetramethyl-benzidine and H2O2 as peroxidase substrates. The results showed that the peroxidase-like activities of the MnFe2O4 NPs were size- and shape-dependent and followed the order of 4 nm (spherical) > 18 nm (plate-like) > 27 nm (near-cubic) > 16 nm (spherical); this order was closely related to their surface-to-volume ratio and atom arrangements. Such an investigation is of great significance for peroxidase nanomimetics with enhanced activity and utilization. Furthermore, folic acid (FA)-conjugated MnFe2O4 NPs allow the detection of folate receptor-rich cancer cells. Such investigation can be widely utilized for the identification of important target molecules.

The application of nanohybrids in water treatment by the catalytic degradation of various pollutants has attracted much attention from researchers. Here, the Pd/Fe3O4-PEI-RGO nanohybrids (1d) with high shape selectivity and high specific surface area have been synthesized by the dispersion of Pd NPs and Fe3O4 NPs on PEI modified graphene oxide sheets. These nanohybrids show superior catalytic activity toward methylene blue with a high degradation efficiency above 99% in the presence of NaBH4 in aqueous solution, which is attributed to the effects of the Pd NPs supported on reduced graphene oxide nanosheets. Meanwhile, the 1d catalyst can be easily separated from the reaction mixture by applying an external magnetic field. The catalyst was recycled nine times without showing any significant loss in its activity. Such features enable this catalyst for promising application in catalysis, environment, and new energy fields.

Recent studies have suggested that the physical and chemical properties of nanoparticles (NPs) strongly depend on local chemical composition, size, and shape. Here, we report a new precursor-mediated growth of monodisperse magnetic cobalt ferrite (CoFe2O4) NPs with controlled size and shape. CoFe2O4 NPs with near corner-grown cubic, near cubic and polyhedron shape can be successfully prepared by simply tuning the amount of iron and cobalt acetylacetonates in oleic acid. Interestingly, the product shape varies from near corner-grown cubic to starlike by only changing the reaction temperature from 320 °C to 330 °C. These CoFe2O4 NPs exhibit size and shape-dependent peroxidase-like activity towards 3,3′,5,5′-tetramethylbenzdine (TMB) in the presence of H2O2, and thus exhibited different levels of peroxidase-like activities, in the order of spherical > near corner-grown cubic > starlike > near cubic > polyhedron; this order was closely related to their particle size and crystal morphology. CoFe2O4NPs exhibited high stability in HAc–NaAc buffer (pH = 4.0) and high activity over a broad pH (2.5–6.0). Furthermore, the Michaelis constants Km value for the CoFe2O4 NPs (0.006 mM) with TMB as the substrate was lower than HRP (0.062 mM) and Fe3O4 NPs (0.010 mM). After further surface functionalization with folic acid (FA), the folate-conjugated CoFe2O4 nanoparticles allow discrimination of HeLa cells (folate receptor overexpression) from NIH-3T3 cells (without folate receptor expression). Such investigation is of great significance for peroxidase nanomimetics with enhanced activity and utilization.

Successful development of magnetic nanoparticles (MNPs) with optimal size, shape, and composition is very desirable because they would increase the image contrast of magnetic resonance imaging (MRI). Here, we report a new precursor-mediated growth process of monodisperse MnFe2O4 NPs with controlled size and shape. MnFe2O4 NPs with plate-like shapes, spherical, and cubic can be successfully prepared by simply tuning the amount of Fe(acac)3 and Mn(acac)2 in oleic acid. Magnetism and MR properties of the particles were found to depend on their size and shape. These MnFe2O4 NPs, when conjugated with gadolinium and folic acid (FA), showed a simultaneous bright signal enhancement on the T1-weighted images and significant signal reduction on the T2-weighted image. In vitro MR imaging experiments also show that the developed multifunctional Gd:FA-DTPA-PEG-DIB-MnFe2O4 NPs enable targeted dual-contrast T1- and T2-weighted MR imaging of tumor cells over-expresses the folate receptor in vitro, and the T1- and T2-weighted MRI has been greatly improved. Our results clearly indicate that such an approach of forming multifunctional Gd:FA-DTPA-PEG-DIB-MnFe2O4 NPs is of great significance for T1- and T2-weighted MR imaging of specific cancer cells with high accuracy.

Ultrasensitive, accurate detection and separation of heavy metal ions is very important in environmental monitoring and biological detection. In this paper, a highly sensitive and specific detection method for Cu2+ based on the fluorescence quenching of a europium(III) hybrid magnetic nanoprobe is presented. This nanoprobe can detect Cu2+ over a wide pH range (5.0–10.0) with a detection limit as low as 0.1 nM and it can be used for detecting Cu2+ in living cells. After the magnetic separation, the Cu2+ concentration decreased to 1.18 ppm, which is less than the US EPA drinking water standard (1.3 ppm), and more than 70% Cu2+ could be removed when the amount of nanocomposite 1 reached 1 mg.

•The new Schiff-base ligand (1) was easily synthesized and widely available.•The compound 1 exhibited a high selectivity and sensitivity toward Al3+ in ethanol.•The detection limit of 1 to Al3+ was up to 0.67 ppb.•Potential utilization of 1 as intracellular sensors of Al3+ ions was also examined.A new Schiff-base ligand (1) with good fluorescence response to Al3+, derived from 2-oxo-quinoline-3-carbaldehyde and nicotinic hydrazide, had been synthesized and investigated in this paper. Spectroscopic investigation revealed that the compound 1 exhibited a high selectivity and sensitivity toward Al(III) ions over other commonly coexisting metal ions in ethanol, and the detection limit of Al3+ ions is at the parts per billion level. The mass spectra and Job’s plot confirmed the 1:1 stoichiometry between 1 and Al3+. Potential utilization of 1 as intracellular sensors of Al3+ ions in human cancer (HeLa) cells was also examined by confocal fluorescence microscopy.

Fe3O4 nanoparticles (NPs) decorated with rhodamine 6G Schiff base, which exhibit high selectivity and sensitivity toward Al3+ over other common metal ions in aqueous media under a physiological pH window via a 1:1 binding mode, have been synthesized and characterized. The resulting conjugate 1c renders the rhodamine 6G Schiff base unit more water soluble, and the detection limit reaches 0.3 ppb in water. Moreover, 1c can detect Al3+ in a wide pH span (5.0–11.0) and enrich/remove excess Al3+ in water via an external magnetic field, which indicates that it has more potential and further practical applications for biology and toxicology. Furthermore, 1c provides good fluorescent imaging of Al3+ in living cells.

The construction of reduced graphene oxide or graphene oxide (GO) with magnetic nanoparticles has gained more and more attention due to its promising and wide applications in catalysis, photoelectric materials, biomedical fields and so on. The synthesis of reduced graphene oxide (RGO) or graphene magnetic nanoparticle nanocomposites with well-dispersed decorated particles is still a challenge. Herein, we first report a simple method to prepare graphene–Fe3O4 with uniform Fe3O4 NPs based on decomposition of Fe(CO)5 on the surface of graphene oxide. The main novelty of this work is that the decomposition products of Fe(CO)5 reacted with GO leading to the formation of graphene–Fe3O4. The resulting sample can be easily manipulated by an external magnetic field and exhibits excellent catalytic activity in the A3-coupling reaction. A diverse range of propargylamines were obtained in a moderate to high yield under mild conditions. The separation and reuse of graphene–Fe3O4 were very simple, effective and economical.

A multifunctional nanoprobe, which can be used for dual modal imaging and the detection of cancer cells, has been reported.

A new three-dimensional (3D) mesoporous hybrid framework was synthesized by coordinated layer-by-layer assembly between nanosheets of reduced graphene oxide and Fe3O4@Cu2O. This 3D mesoporous framework shows an excellent catalytic performance with a remarkable activity, selectivity (>99%), and strong durability in the synthesis of quinoxalines.

Successful development of magnetic nanoparticles (MNPs) with optimal size, shape, and composition is very desirable because they would increase the image contrast of magnetic resonance imaging (MRI). Here, we report a new precursor-mediated growth process of monodisperse MnFe2O4 NPs with controlled size and shape. MnFe2O4 NPs with plate-like shapes, spherical, and cubic can be successfully prepared by simply tuning the amount of Fe(acac)3 and Mn(acac)2 in oleic acid. Magnetism and MR properties of the particles were found to depend on their size and shape. These MnFe2O4 NPs, when conjugated with gadolinium and folic acid (FA), showed a simultaneous bright signal enhancement on the T1-weighted images and significant signal reduction on the T2-weighted image. In vitro MR imaging experiments also show that the developed multifunctional Gd:FA-DTPA-PEG-DIB-MnFe2O4 NPs enable targeted dual-contrast T1- and T2-weighted MR imaging of tumor cells over-expresses the folate receptor in vitro, and the T1- and T2-weighted MRI has been greatly improved. Our results clearly indicate that such an approach of forming multifunctional Gd:FA-DTPA-PEG-DIB-MnFe2O4 NPs is of great significance for T1- and T2-weighted MR imaging of specific cancer cells with high accuracy.

A multifunctional nanoprobe, which can be used for dual modal imaging and the detection of cancer cells, has been reported.

The catalytic activity of nanocrystal catalysts depends strongly on their chemical composition, size, and shape. Herein, we report four different sizes and shapes of MnFe2O4 nanoparticles (NPs) prepared by a hydrothermal procedure. In addition, the size- and shape-dependent peroxidase-like activity of these NPs was first explored using 3,3′,5,5′-tetramethyl-benzidine and H2O2 as peroxidase substrates. The results showed that the peroxidase-like activities of the MnFe2O4 NPs were size- and shape-dependent and followed the order of 4 nm (spherical) > 18 nm (plate-like) > 27 nm (near-cubic) > 16 nm (spherical); this order was closely related to their surface-to-volume ratio and atom arrangements. Such an investigation is of great significance for peroxidase nanomimetics with enhanced activity and utilization. Furthermore, folic acid (FA)-conjugated MnFe2O4 NPs allow the detection of folate receptor-rich cancer cells. Such investigation can be widely utilized for the identification of important target molecules.

The three-dimensional porous Fe3O4@Cu2−xS–MoS2 framework is reported for the first time. The as-prepared 3D framework exhibits good structural stability, high surface area, enhanced adsorption capacity to substrates, and strong absorption in the NIR range. As a result, such hybrid frameworks exhibit excellent NIR-light photocatalytic activity and stable cycling for the direct arylation of heteroaromatics at room temperature.

The application of nanohybrids in water treatment by the catalytic degradation of various pollutants has attracted much attention from researchers. Here, the Pd/Fe3O4-PEI-RGO nanohybrids (1d) with high shape selectivity and high specific surface area have been synthesized by the dispersion of Pd NPs and Fe3O4 NPs on PEI modified graphene oxide sheets. These nanohybrids show superior catalytic activity toward methylene blue with a high degradation efficiency above 99% in the presence of NaBH4 in aqueous solution, which is attributed to the effects of the Pd NPs supported on reduced graphene oxide nanosheets. Meanwhile, the 1d catalyst can be easily separated from the reaction mixture by applying an external magnetic field. The catalyst was recycled nine times without showing any significant loss in its activity. Such features enable this catalyst for promising application in catalysis, environment, and new energy fields.

A high-performance imaging probe with NIR luminescence and synergistically enhanced T1−T2 relaxivity was synthesized. This nanoprobe exhibits a relatively high tumor-targeting efficacy and enables NIR optical and T1-/T2-weighted MR imaging of hepatic tumor cells in vivo.

We successfully synthesized blue, green, and red CsPbX3 QDs-codoped flexible films using a one-step electrospun strategy, followed by coating a strongly hydrophobic silicone resin on the surface of the films. The codoped flexible light-emitting films are resistant to water, thereby preventing anion exchange and significantly prolonging the lifetime of light emitters under ambient air conditions.

A novel atom-scale interfacial coordination assisted synthesis method for the textural engineering of three-dimensional (3D) Fe3O4–graphene oxide frameworks with hierarchical macro- and meso-porous structures is developed.

The construction of reduced graphene oxide or graphene oxide (GO) with magnetic nanoparticles has gained more and more attention due to its promising and wide applications in catalysis, photoelectric materials, biomedical fields and so on. The synthesis of reduced graphene oxide (RGO) or graphene magnetic nanoparticle nanocomposites with well-dispersed decorated particles is still a challenge. Herein, we first report a simple method to prepare graphene–Fe3O4 with uniform Fe3O4 NPs based on decomposition of Fe(CO)5 on the surface of graphene oxide. The main novelty of this work is that the decomposition products of Fe(CO)5 reacted with GO leading to the formation of graphene–Fe3O4. The resulting sample can be easily manipulated by an external magnetic field and exhibits excellent catalytic activity in the A3-coupling reaction. A diverse range of propargylamines were obtained in a moderate to high yield under mild conditions. The separation and reuse of graphene–Fe3O4 were very simple, effective and economical.