A review on ZnS-based photocatalysts for CO2 reduction in all-inorganic aqueous medium.

Photocatalytic CO2 reduction mimics natural photosynthesis, which is a potential technology for "carbon neutrality". This article will review the recent research progress of a class of distinguished photocatalytic CO2 reduction systems based on ZnS nanocrystal photocatalysts. We will focus on the pathway of maximizing the photoreduction rate of CO2 by continuously optimizing the catalyst design and the composition of the reaction medium. Such discussions will be meaningful and beneficial for developing universal strategies of solar fuel production. Finally, an outlook will be provided to brighten the prospects of ZnS-based photocatalytic CO2 reduction systems.

A rod-like melem with high fluorescence quantum yield for sensitive detection of reduced glutathione.

A rod-like melem with high fluorescence quantum yield of 71.3 % was prepared in this work to enhance the chemiluminescence (CL) intensity of Na2SO3-Ce (Ⅳ) system. The results showed that the CL intensity of Na2SO3-Ce (Ⅳ) system could be increased by 350 times based on chemiluminescence resonance energy transfer (CRET) mechanism. Furthermore, a CL sensor based on Na2SO3-Ce (Ⅳ)-melem system was designed to detect reduced glutathione (G-SH). It was indicated that the CL sensor exhibited excellent G-SH detection performance with a detection limit of 0.065 nM and a linear range from 0.32 to 650 µM. This study applied melem for CL detection and provided a new way for the detection of G-SH.

Au Modified F-TiO2 for Efficient Photocatalytic Synthesis of Hydrogen Peroxide.

In this work, Au-modified F-TiO2 is developed as a simple and efficient photocatalyst for H2O2 production under ultraviolet light. The Au/F-TiO2 photocatalyst avoids the necessity of adding fluoride into the reaction medium for enhancing H2O2 synthesis, as in a pure TiO2 reaction system. The F- modification inhibits the H2O2 decomposition through the formation of the ≡Ti-F complex. Au is an active cocatalyst for photocatalytic H2O2 production. We compared the activity of TiO2 with F- modification and without F- modification in the presence of Au, and found that the H2O2 production rate over Au/F-TiO2 reaches four times that of Au/TiO2. In situ electron spin resonance studies have shown that H2O2 is produced by stepwise single-electron oxygen reduction on the Au/F-TiO2 photocatalyst.

A ß-cyclodextrin Modified Graphitic Carbon Nitride with Au Co-Catalyst for Efficient Photocatalytic Hydrogen Peroxide Production.

Photocatalytic hydrogen peroxide (H2O2) production has attracted considerable attention as a renewable and environment-friendly method to replace other traditional production techniques. The performance of H2O2 production remains limited by the inertness of graphitic carbon nitride (CN) towards the adsorption and activation of O2. In this work, a photocatalyst comprising of ß-cyclodextrin (ß-CD)-modified CN with supporting Au co-catalyst (Au/ß-CD-CN) has been utilized for effective H2O2 production under visible light irradiation. The static contact angle measurement suggested that ß-CD modification increased the hydrophobicity of the CN photocatalyst as well as its affinity to oxygen gas, leading to an increase in H2O2 production. The rate of H2O2 production reached more than 0.1 mM/h under visible-light irradiation. The electron spin resonance spectra indicated that H2O2 was directly formed via a 2-electron oxygen reduction reaction (ORR) over the Au/ß-CD-CN photocatalyst.

[Zoledronate regulates osteoclast differentiation and bone resorption in high glucose through p38 MAPK pathway].

OBJECTIVE: To investigate the effect of zoledronate (ZOL) on osteoclast differentiation and bone resorption under high glucose, and the regulation mechanism of p38 mitogen activated kinase (p38 MAPK) signaling pathway in this process. METHODS: RAW264.7 cells were divided into four groups: low group, high group, low+ZOL group and high+ZOL group after induced into osteoclasts. Cell proliferation activity was determined by MTT assay. The migration of RAW264.7 cells were examined Optical microscopy. Immunofluorescence microscopy was used to observe the cytoskeleton and sealing zones of osteoclasts. After adding group 5: high + ZOL + SB203580 group, trap staining was used to identify the number of positive osteoclasts in each group. The number and area of resorption lacunae were observed by SEM. The mRNA and protein expression of osteoclast related factors were detected by real-time PCR and Western blotting. RESULTS: The cells in the 5 groups showed similar proliferative activity. High glucose promoted the migration of RAW264.7 cells (P < 0.05), inhibited the clarity of cytoskeleton and the formation of sealing zones in the osteoclasts. Exposure to high glucose significantly lowered the expressions of p38 MAPK, p-p38 MAPK, NFATc1, CTSK and TRAP, and inhibited osteoclast differentiation and bone absorption (P < 0.05). Treatment with ZOL obviously suppressed the migration ability of RAW264.7 cells, further reduced the clarity of the cytoskeleton, inhibited the formation of sealing zones of the osteoclasts, lowered the expressions of p38 MAPK, p-p38 MAPK, NFATc1, CTSK, and TRAP (P < 0.05), and inhibited osteoclast differentiation and bone absorption. Treatment with SB203580 obviously inhibited osteoclast differentiation and bone resorption and the expressions of P38 MAPK, p-p38 MAPK, NFATc1, CTSK and TRAP (P < 0.05). CONCLUSIONS: High glucose inhibits osteoclast differentiation and bone resorption. ZOL inhibits osteoclast differentiation and bone resorption in high-glucose conditions by regulating p38 MAPK pathway, which can be a new pathway for ZOL to regulate diabetic osteoporosis.

A novel "turn-on" fluorescent sensor for hydrogen peroxide based on oxidized porous g-C3 N4 nanosheets.

An oxidized, porous graphitic carbon nitride nanosheets (CNNs) was successfully obtained via a bottom-up approach. The inner filter effect (IFE) of Fe (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachlorideporphyrin pentachloride (FeTMPyP) on the CNNs results in fluorescence quenching of the CNNs due to the overlap of FeTMPyP absorbance band and CNNs emission band. It is interesting that the quenched fluorescence could be "turned on" in response to the participation of H2 O2 , which caused by decomposition of FeMPyP. In this study, for the first time, a porous fluorescence probe based on CNNs and FeTMPyP was designed and an excellent H2 O2 detection performance with a large detection range of 0.1 ~ 100 µM and a detection limit of 0.07 µM was achieved. Furthermore, the proposed method was successfully used for H2 O2 detection in RAW 264.7 cells.

A hybrid material composed of graphitic carbon nitride and magnetite (Fe3O4) for magnetic solid-phase extraction of trace levels of hydroxylated polycyclic aromatic hydrocarbons.

Magnetic carbon nitride composites were synthesized via a solvothermal reaction and developed as an effective adsorbent for magnetic solid-phase extraction of trace hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) from urine samples prior to their determination by HPLC. The sorbent was characterized by Fourier transform infrared spectrometry, X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry and solvent stability experiments. The adsorption of hydroxy-PAHs is better by a factor or 20 to 49 compared to bare Fe3O4 and comparable that of a commercial C18 sorbent. The adsorbent amount, adsorption time and eluting solvent and volume were optimized. The complete extraction for the OH-PAHs at a level of 40 ng·mL-1 and by using 4 mg sorbent is completed within 3 min. With an enzymatic hydrolyzed urine sample loading volume of 2 mL, enhancement factors in the range of 9-10, and a limit of detection (at S/N = 3) of 0.08 ng·mL-1 were achieved. The method showed a linear response in the 0.25-250 ng·mL-1 hydroxy-PAH concentration range, and intra-day and inter-day precisions are 1.5-7.7% and 2.2-8.7%, respectively. The recovery from spiked urine samples ranged from 90.1% to 102%. The sorbent was stable over 10 successive cycles of extraction/desorption of urine sample without significant loss of extraction efficiency. The method was successfully applied for the determination of OH-PAHs in urine samples of smoking volunteers. Graphical abstract Schematic presentation of the preparation of graphitic carbon nitride (g-C3N4)/magnetite (Fe3O4) using a solvothermal reaction, and application for magnetic solid-phase extraction of three trace hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) in urine samples of smoking volunteers.

Correction to: Self assembly and controlled drug release of a nano-laminated graphite carbon nitride/methotrexate complex.

The original version of this article unfortunately contained a mistake. In the Abstract section the sentence "Furthermore, the drug release mechanism was investigated by kinetic models and a first-order relationship was concluded, which indicated that the drug release is a simple diffusion process cohydroxyapatite/methotrexate complexntrolled by gradient drug concentration." was wrong. It should read as "Furthermore, the drug release mechanism was investigated by kinetic models and a first-order relationship was concluded, which indicated that the drug release is a simple diffusion process controlled by gradient drug concentration."

Self assembly and controlled drug release of a nano-laminated graphite carbon nitride/methotrexate complex.

In this study, g-C3N4/methotrexate (g-C3N4/MTX) nanohybrids were obtained via a self assembly method. XRD and TEM demonstrated that bulk g-C3N4 had been stripped into thin nanosheets with size range of 150-250 nm. FTIR investigation indicated that the self assembly of the hybrid was attributed to the hydrogen bond between g-C3N4 nanosheets and MTX molecules. It is confirmed by the UV-vis spectra that the hybrids can achieve a sustained drug release within long period for 70 h. Furthermore, the drug release mechanism was investigated by kinetic models and a first-order relationship was concluded, which indicated that the drug release is a simple diffusion process cohydroxyapatite/methotrexate complexntrolled by gradient drug concentration. Cell viability tests confirmed that g-C3N4 presented excellent biocompatibility and g-C3N4/MTX hybrids had obvious suppression efficiency on MG63 cells which showed a positive correlation to the drug concentration and incubation time.

Magnetic Lamellar Nano-Hydroxyapatite as a Vector for Gene Transfection in Three-Dimensional Cell Culture.

Compared to two-dimensional (2D) conditions, investigation on gene transfection in three-dimensional (3D) conditions is much less extensive. In this work, lamellar nano-hydroxyapatite (L-HAp) with and without magnetism were used as the vectors and gene transfection in 2D and 3D cell culture was carried out and compared. We found that the transfection efficiency in 3D conditions was much higher than 2D cell culture. Additionally, magnetism enhanced transfection efficiency under both 2D and 3D conditions. The findings presented in this study demonstrated that the magnetic L-HAp could be a promising vector in 3D gene transfection.

Engineering photoluminescent and magnetic lamellar hydroxyapatite by facile one-step Se/Gd dual-doping.

The design and synthesis of multifunctional hydroxyapatite (HAp) nanoparticles are important in expanding their clinical applications. Herein we report a novel selenium (Se) and gadolinium (Gd) dual-doped lamellar hydroxyapatite (L-HAp-Se-Gd) produced by facile one-step template-assisted synthesis. The results show that the as-prepared L-HAp-Se-Gd nanoparticles exhibit obvious changes in morphology, dimensions, and crystallinity as compared to bare L-HAp. XRD results reveal that high dopant levels of Se and Gd reduce the degree of ordering of HAp lamellae. It is found that the L-HAp-Se-Gd nanoparticles display Gd content-dependent blue fluorescence under ultraviolet (UV) irradiation and magnetic properties. Cell tests with mouse embryo osteoblast cells (MC3T3-E1) reveal their improved biocompatibility over bare L-HAp due to Se incorporation. These results indicate that L-HAp-Se-Gd nanoparticles have potential in numerous applications such as multifunctional gene delivery and bioimaging.

Morphology effect of nano-hydroxyapatite as a drug carrier of methotrexate.

In this study, morphology effect of nano-hydroxyapatite as a drug carrier was investigated for the first time. Hydroxyapatite/methotrexate (HAp/MTX) hybrids with different morphologies were successfully prepared in situ using polyethylene glycol (PEG) as a template. SEM, TEM, XRD and FTIR results confirmed that the hybrids of different morphologies (laminated, rod-like and spherical) with similar phase composition and functional groups were obtained by changing the preparation parameters. UV-Vis spectroscopy was used to identify the drug loading capacity and drug release mechanism of the three hybrids with different morphologies. It is concluded that the laminated hybrid exhibits a higher drug loading capacity compared to the other two hybrids, and all the three hybrids showed a sustained slow release which were fitted well by Bhaskar equation. Additionally, the result of in vitro bioassay test confirms that the inhibition efficacy of the three hybrids showed a positive correlation to the drug loading capacity.

Mechanical properties and cytotoxicity of nanoplate-like hydroxyapatite/polylactide nanocomposites prepared by intercalation technique.

Hydroxyapatite (HAp) in the forms of fiber, needle, and whisker has been employed as fillers in polymer composites. Herein, nanoplate-like HAp synthesized by template-assisted self-assembly was used to reinforce polylactide (PLA) nanocomposites via the solution intercalation method. Dynamic and static mechanical properties and cytotoxicity of the as-prepared HAp/PLA nanocomposites were assessed in addition to characterizations by XRD, FTIR, and TGA. XRD analysis confirms the formation of exfoliated structure in the HAp/PLA nanocomposites. The HAp/PLA nanocomposites exhibit better static and dynamic mechanical properties than unreinforced PLA. Furthermore, the HAp/PLA nanocomposite with an optimum HAp content of 20wt% (20HAp/PLA) demonstrates not only the best mechanical performance but also the highest thermal stability among the nanocomposite samples. Cell studies using a mouse fibroblast cell line (L929) suggest that 20HAp/PLA shows excellent biocompatibility, which makes it a promising material for biomedical applications.

The inhibition of lamellar hydroxyapatite and lamellar magnetic hydroxyapatite on the migration and adhesion of breast cancer cells.

Hydroxyapatite nanoparticles have been reported to exhibit potent anti-tumor effects in some cancer cells. In our previous study, we have successfully synthesized two types of hydroxyapatite nanoparticles, laminated hydroxyapatite (L-HAp) and laminated magnetic hydroxyapatite (LM-HAp). In this study, we wanted to investigate the effects of L-HAp and LM-HAp with various concentrations on human breast cancer MDA-MB-231 cells. Cell proliferation was assessed with a MTT colorimetric assay. Scratch and adhesion assays were used to detect the effects of these two materials on migration and adhesion. The expressions of integrin ß1 and Akt were measured by Western blotting. Our results showed that L-HAp and LM-HAp had little cell cytotoxicity and significantly reduced cell mobility and adhesion. LM-HAp showed greater inhibitor ability on migration and adhesion of MDA-MB-231 cells. Moreover, results from western blotting showed that L-HAp and LM-HAp impacted the phosphorylation of integrin ß1, but showed no regular impact on Akt. This study suggests that L-HAp and LM-HAp may be potential anti-tumor and delivery system for breast cancer therapy.