Multiple-Emitting Luminescent Metal-Organic Framework as an Array-on-a-MOF for Rapid Screening and Discrimination of Nitroaromatics.

Fluorescence array technologies have attracted great interest in the sensing field because of their high sensitivity, low cost, and capability of multitarget detection. However, traditional array sensing relies on multiple independent sensors and thus often requires time-consuming and laborious measurement processes. Herein, we introduce a novel fluorescence array strategy of the array-on-a-metal-organic framework (MOF), which integrates multiple array elements into a single MOF matrix to achieve facile sensing and discrimination of multiple target analytes. As a proof-of-concept system, we constructed a luminescent MOF containing three different emitting channels, including a lanthanide ion (europium/Eu3+, red emission), a fluorescent dye (7-hydroxycoumarin-4-acetic acid/HCAA, blue emission), and the MOF itself (UiO-66-type MOF, blue-violet emission). Five structurally similar nitroaromatic compounds (NACs) were chosen as the targets. All three channels of the array-on-a-MOF displayed rapid and stable fluorescence quenching responses to NACs (response equilibrium achieved within 30 s). Different responses were generated for each channel against each NAC due to the various quenching mechanisms, including photoinduced electron transfer, energy competition, and the inner filter effect. Using linear discriminant analysis, the array-on-a-MOF successfully distinguished the five NACs and their mixtures at varying concentrations and demonstrated good sensitivity to quantify individual NACs (detect limit below the advisory concentration in drinking water). Moreover, the array also showed feasibility in the sensing and discrimination of multiple NACs in real water samples. The proposed "array-on-a-MOF" strategy simplifies multitarget discrimination procedures and holds great promise for various sensing applications.

Universal occurrence of organophosphate tri-esters and di-esters in marine sediments: Evidence from the Okinawa Trough in the East China Sea.

Despite numerous data on organophosphate tri-esters (tri-OPEs) in the environment, literatures on organophosphate di-esters (di-OPEs) in field environment, especially marine sediments remain scarce. This study addresses this gap by analyzing 35 abyssal sediment samples from the middle Okinawa Trough in the East China Sea. A total of 25 tri-OPEs and 10 di-OPEs were determined, but 13 tri-OPEs and 2 di-OPEs were nondetectable in any of these sediment samples. The concentrations of ∑12tri-OPE and ∑8di-OPE were 0.108-32.2 ng/g (median 1.11 ng/g) and 0.548-15.0 ng/g (median 2.74 ng/g). Chlorinated (Cl) tri-OPEs were the dominant tri-esters, accounting for 47.5 % of total tri-OPEs on average, whereas chlorinated di-OPEs represented only 19.2 % of total di-OPEs. This discrepancy between the relatively higher percentage of Cl-tri-OPEs and lower abundance of Cl-di-OPEs may be ascribed to the stronger environmental persistence of chlorinated tri-OPEs. Source assessment suggested that di-OPEs were primarily originated from the degradation of tri-OPEs rather than industrial production. Long range waterborne transport facilitated by oceanic currents was an important input pathway for OPEs in sediments from the Okinawa Trough. These findings enhance the understanding of the sources and transport of OPEs in marine sediments, particularly in the Okinawa Trough.

Nano-Hydroxyapatite Composite Scaffolds Loaded with Bioactive Factors and Drugs for Bone Tissue Engineering.

Nano-hydroxyapatite (n-HAp) is similar to human bone mineral in structure and biochemistry and is, therefore, widely used as bone biomaterial and a drug carrier. Further, n-HAp composite scaffolds have a great potential role in bone regeneration. Loading bioactive factors and drugs onto n-HAp composites has emerged as a promising strategy for bone defect repair in bone tissue engineering. With local delivery of bioactive agents and drugs, biological materials may be provided with the biological activity they lack to improve bone regeneration. This review summarizes classification of n-HAp composites, application of n-HAp composite scaffolds loaded with bioactive factors and drugs in bone tissue engineering and the drug loading methods of n-HAp composite scaffolds, and the research direction of n-HAp composite scaffolds in the future is prospected.

Organophosphate tri-esters and di-esters in drinking water and surface water from the Pearl River Delta, South China: Implications for human exposure.

Some organophosphate di-esters (di-OPEs) have been found to be more toxic than their respective tri-esters. The environmental occurrence of di-OPEs remains largely unclear. A total of 106 water samples, including 56 drinking water (bottled, barreled, and tap water) and 50 surface water (lake and river) samples were collected and analyzed for 10 organophosphate tri-esters (tri-OPEs) and 7 di-OPEs. The concentrations (range (median)) of ∑7di-OPE were 2.8-22 (9.7), 1.1-5.8 (2.6), 3.7-250 (120), 13-410 (220), and 92-930 (210) ng/L in bottled water, barreled water, tap water, lake water, and river water, respectively. In all types of water samples, tris(1-chloro-2-propyl) phosphate was the dominant tri-OPE compound. Diphenyl phosphate was the predominant di-OPE compound in tap water and surface water, while di-n-butyl phosphate and bis(2-ethylhexyl) phosphate was the dominant compound in bottled water and barreled water, respectively. Source analysis suggested diverse sources of di-OPEs, including industrial applications, effluents of municipal wastewater treatment plants, degradation from tri-OPEs during production/usage and under natural environmental conditions. The non-carcinogenic and carcinogenic risks of OPEs were lower than the theoretical threshold of risk, indicating the human health risks to OPEs via drinking water consumption were negligible. More studies are needed to explore environmental behaviors of di-OPEs in the aquatic environment and to investigate ecological risks.

Covalent Cross-Linking of Metal-Organic Cages: Formation of an Amorphous Cationic Porous Extended Framework for the Uptake of Oxo-Anions from Water.

Invited for this month's cover are the collaborating groups of Sheng-Run Zheng and Wei-Guang Zhang from South China Normal University, China. The cover picture shows an amorphous cationic porous metal-organic material that constructed from the covalent linking of large cationic metal-organic cage for the removal of toxic oxo-anions from water with high capacities and rapid kinetics. Read the full text of the article at 10.1002/cplu.202000570.

Covalent Cross-Linking of Metal-Organic Cages: Formation of an Amorphous Cationic Porous Extended Framework for the Uptake of Oxo-Anions from Water.

Cationic amorphous metal-organic cage (MOC)-based materials capable of removing anionic pollutants from water are receiving increasing attention but they are still relatively less reported. Herein, for the first time, a cationic porous MOC-based extended framework, namely, CL-aMOC-1, was constructed by covalent linking of a cationic Pd12 L24 (L=3,5-di-pyridin-4-yl-benzaldehyde) cage with a 1,4-bis(4-aminophenyl)benzene (BAPB) linker. Interestingly, the reaction could be completed within 15 min using an amorphous MOC-based solid (aMOC-1) and BAPB as reactant via a low-temperature solid-state reaction. The CL-aMOC-1 showed improved stability, lower solubility and higher oxo-anion uptake in water compared with the original aMOC-1. The adsorption capacities for CrO4 2- , Cr2 O7 2- and ReO4 - on CL-aMOC-1 were 245.1, 311.5 and 452.5 mg/g, respectively, in which the uptake of Cr(VI)-containing oxo-anions was among the highest compared with those of other metal-organic materials. The CL-aMOC-1 can selectively capture oxo-anions in the presence of competitive anions. It exhibits good reusability as over 85 % of the uptake capacity is retained after 5 cycles. Finally, it shows the ability to remove Cr(VI) ions from electroplating wastewater.

Homochiral Cu(I) Coordination Polymers Based on a Double-Stranded Helical Building Block from Achiral Ligands: Symmetry-Breaking Crystallization, Photophysical and Photocatalytic Properties.

A pair of homochiral coordination polymers, [Cu(DPT)]n (1M and 1P, HDPT = 3,5-di-4-pyridinyl-2H-tetrazole), were assembled from achiral precursors. Crystal structure analysis showed that they are chiral three-dimensional (3D) coordination polymers based on a new double-stranded helical building block that is composed of two different 1D helices. Interestingly, rare symmetry-breaking crystallization was observed, in which the possibility of obtaining enantio-enriched bulk product with excessive M enantiomers (1-A) was obviously higher than that for P enantiomers (1-B) as demonstrated in multiple, repeated experiments with single-crystal diffraction and vibrational circular dichroism (VCD) spectra. Moreover, compound [Cu(DPT)]n shows good chemical stability in water, with pH values ranging from 3 to 13, as well as in many common organic solvents. Photophysical properties, including thermochromic properties and two-photon excited luminescence, were studied, and the potential for applications in temperature sensing was exhibited. In addition, the photocatalytic degradation of methylene blue in water indicated that compound [Cu(DPT)]n can be used as a photocatalyst.

An Anionic Nanotubular Metal-Organic Framework for High-Capacity Dye Adsorption and Dye Degradation in Darkness.

A metal-organic framework (MOF), named SCNU-Z2, based on a new heterotopic tripodal nitrogen-containing ligand, has been constructed. Due to the replacement of one imidazole group in the reported ligand with one tetrazole group, the charge of the framework is changed from cationic to anionic but retains the same framework structure. The framework consists of tubular channels with a diameter of 1.5 nm and exhibits satisfactory stability in water with a pH range of 3-11. The anionic nature of the framework allows the effective adsorption of the cationic dyes MLB, CV, and RhB with capacities of 455.6, 847.4, and 751.8 mg/g, respectively. Among them, the adsorption capacities for SCNU-Z2 on CV and RhB rank as the highest when compared with other reported MOFs. In contrast, SCNU-Z2 exhibits an extremely low capacity for anionic dyes MO and AO, making it useful for the separation of anionic and cationic dyes based on a charge-dependent mode. Interestingly, SCNU-Z2 can be used to degrade an anionic dye, MB, within 30 min under darkness at room temperature. The apparent activation energy of the dye degradation reaction is calculated to be approximately 18.96 kJ·mol-1, implying that the catalytic reaction of MB can be considered as a low-temperature thermocatalytic reaction in the dark/SCNU-Z2 system.

Hydrolytically Stable Nanotubular Cationic Metal-Organic Framework for Rapid and Efficient Removal of Toxic Oxo-Anions and Dyes from Water.

Cationic framework materials capable of removing anionic pollutants from wastewater are highly desirable but relatively rarely reported. Herein, a cationic MOF (SCNU-Z1-Cl) possessing tubular channels with diameter of 1.5 nm based on Ni(II) and a nitrogen-containing ligand has been synthesized and applied to capture hazardous anionic contaminants from water. The SCNU-Z1-Cl exhibits high BET surface area of 1636 m2/g, and shows high hydrolytically stability in pH range from 4 to 10. Owing to the large tubular channels and the uncoordinated anions in the framework, the aqueous-phase anion-exchange applications of SCNU-Z1-Cl were explored with environmentally toxic oxo-anions including CrO42-, Cr2O72-, MnO4-, and ReO4-, and organic dyes. The adsorption of oxoanions exhibits high uptake kinetics and the adsorption capacities of CrO42-, Cr2O72-, MnO4-, and ReO4- are 126, 241, 292, and 318 mg/g, respectively, which were some of the highest values in the field of MOF/COF. In additional, the selectively is high when other concurrent anions are exist. The anionic dyes with different sizes including methyl orange, acid orange A, congo red, as well as methyl blue can be adsorbed by SCNU-Z1-Cl in few minutes to about 1 h. The adsorption capacities for them are 285, 180, 585, and 262 mg/g, respectively. In contrast, the adsorption kinetics for catinionic dyes with different sizes is obviously lower and exhibit a size-selectively adsorption that only cationic dye with suitable size (rhodamine B) can be adsorbed by SCNU-Z1-Cl. Consequently, SCNU-Z1-Cl can sepearate organic dyes in three different modes: size-dependent, charge-dependent, and kinetics-dependent selective adsorption. The excellent adsorption and separation properties of SCNU-Z1-Cl is attribute to the cationic framework, large tubular channel, as well as the high positive Zeta potential.

[Cloning and expression of metalloprotease gene from Schistosoma japonicum and its immunoprotective efficiency].

OBJECTIVE: To clone and express a metalloprotease gene of Schistosoma japonicum, purify the expressed protein, and investigate the induced immune response in mice and its localization in the parasite. METHODS: Specific primers were designed according to the EST sequence and used for amplification of the encoding sequence from the S. japonicum cDNA clone containing S. japonicum metalloprotease. The gene was subcloned into pET-28a plasmid and expressed, and the recombinant protein was purified with HisoTag affinity chromatography. Western blotting was used to analyze the immunogenicity. Eighteen C57BC/6 mice were divided into two groups. Mice in group A were immunized each with 25 microg purified recombinant SjB04 at every 2 weeks for 3 times. Mice in group B received only adjuvant as control. Each mouse was challenged by (40 +/- 2) cercariae at the third week after the last immunization. Fecal samples were collected for 6 days from 37th days after challenge. Eggs per gram feces and rate of egg reduction were calculated. S. japonicum adult worms were collected from infected mice, and used for preparing frozen sections and indirect immunofluorescence staining with specific polyclone antibody to S. japonicum metalloprotease. RESULTS: The metalloprotease gene SjB04 was cloned, sequenced and expressed. The immuno-fluorescence localization showed that SjBO4 protein distributed mainly in the intestinal epithelium of the adult worm. The recombinant protein was specifically recognized by the S. japonicum-infected rabbit sera, showing that the expressed product possessed antigenicity. Mice immunized with the recombinant protein revealed a reduction in number of adult worms, eggs in feces by 27.1% and 57.8%, respectively. CONCLUSION: The recombinant protein of S. japonicum metalloprotease has been obtained with Mr 36,500. The protein locates in the intestinal epithelium of adult worm. Immunization with the SjB04 protein induces significant reduction of fecal eggs.