Engineering an Ag/Au bimetallic nanoparticle-based acetylcholinesterase SERS biosensor for in situ sensitive detection of organophosphorus pesticide residues in food.

Developing simple, efficient, and inexpensive method for trace amount organophosphorus pesticides' (OPs) detection with high sensitivity and specificity is of significant importance for guaranteeing food safety. Herein, an Ag/Au bimetallic nanoparticle-based acetylcholinesterase (AChE) surface-enhanced Raman scattering (SERS) biosensor was constructed for in situ simple and sensitive detection of pesticide residues in food. The principle of this biosensor exploited 4-mercaptophenylboronic acid (4-MPBA)-modified Ag/Au bimetallic nanoprobes as SERS signal probe to improve sensitivity and stability. The combination of AChE and choline oxidase (CHO) can hydrolyze acetylcholine (ATCh) to generate H2O2. The product of H2O2 selectively oxidizes the boronate ester of 4-MPBA, decreasing the Raman intensity of the B-O symmetric stretching. In the presence of OPs, it could inhibit the production of H2O2 by destroying the AChE activity, so the reduction of the SERS signal was also alleviated. Based on the principle, an Ag/Au bimetallic nanoparticle-based AChE SERS sensor was established without any complicated pretreatments. Benefiting from the synergistic effects of Ag/Au bimetallic hybrids, a linear detection range from 5×10-9 to 5×10-4 M was achieved with a limit of detection down to 1.7×10-9 M using parathion-methyl (PM) as the representative model of OPs. Moreover, the SERS biosensor uses readily available reagents and is simple to implement. Importantly, the proposed SERS biosensor was used to quantitatively analyze OP residues in apple peels. The levels of OPs detected in real samples by this method were consistent with those obtained using gas chromatography-mass spectrometry (GC-MS), suggesting the proposed assay has great potential applications for OPs in situ detection in food safety fields.

Blockade of IL-17A/IL-17R Pathway Protected Mice from Sepsis-Associated Encephalopathy by Inhibition of Microglia Activation.

Sepsis-associated encephalopathy (SAE) is a poorly understood condition that leads to long-term cognitive impairment and increased mortality in survivors. Recent research revealed that IL-17A/IL-17R might serve as a checkpoint in microglia-mediated neuroinflammation. The present study was designed to determine the specific role of IL-17A-mediated microglia activation in the development of SAE. A mouse model of SAE was induced by cecal ligation and puncture (CLP), and behavior performance was evaluated by the inhibitory avoidance test and the open field test. Cytokine expression and microglia activation in brain tissue were determined at 6 h, 12 h, 24 h, 48 h, and day 7 post surgery. Further, septic mice were intracerebral ventricle- (i.c.v.-) injected with recombinant IL-17A, anti-IL-17A ab, anti-IL-17R ab, or isotype controls to evaluate the potential effects of IL-17A/IL-17R blockade in the prevention of SAE. Septic peritonitis induced significant impairment of learning memory and exploratory activity, which was associated with a higher expression of IL-17A, IL-1ß, and TNF-α in the brain homogenate. Fluorescence intensity of Iba-1 and IL-17R in the hippocampus was significantly increased following CLP. Treatment with recombinant IL-17A enhanced the neuroinflammation and microglia activation in CLP mice. On the contrary, neutralizing anti-IL-17A or anti-IL-17R antibodies mitigated the CNS inflammation and microglia activation, thus alleviating the cognitive dysfunction. Furthermore, as compared to the sham control, microglia cultured from CLP mice produced significantly higher levels of cytokines and expressed with higher fluorescence intensity of Iba-1 in response to IL-17A or LPS. Pretreatment with anti-IL-17R ab suppressed the Iba-1 expression and cytokine production in microglia stimulated by IL-17A. In conclusion, blockade of the IL-17A/IL-17R pathway inhibited microglia activation and neuroinflammation, thereby partially reversing sepsis-induced cognitive impairment. The present study suggested that the IL-17A/IL-17R signaling pathway had an important, nonredundant role in the development of SAE.

Metal sulfide nanoparticle-based dual barcode-triggered DNAzyme cascade for multiplex miRNA detection in a single assay.

Single miRNAs are not specific and accurate enough to meet the strict diagnosis requirements in practice. Therefore, simultaneous monitoring of multiplexed miRNA in biological samples can not only improve the accuracy and specificity of bioassays but also avoid the squandering of valuable biological specimens. Herein, we designed a metal sulfide nanoparticle-based dual barcode-triggered DNAzyme cascade strategy for the sensitive and simultaneous multiplex miRNA detection in a single assay. Firstly, the capture probes (H1, H2) specifically recognize targets (miRNA-21, miRNA-141), exposing the stem of H1 and H2. Then, with the introduction of a detection probe (CuS-H3, ZnS-H4), the exposed H1 and H2 catalyze the hairpin assembly (CHA) reaction, realizing target miRNA recycling, and forming H1/H3-CuS and H2/H4-ZnS complexes. Subsequently, the formed H1/H3-CuS and H2/H4-ZnS complexes are encoded on magnetic beads through the biotin/streptavidin interaction. The CuS and ZnS nanoparticles captured by magnetic beads release thousands of Cu2+ and Zn2+via the cation exchange reaction. Finally, the released Cu2+ and Zn2+ specially activate the DNAzyme of the catalytic and molecular beacon (CAMB) system. The CAMB system affords an amplified fluorescence signal output by cycling and regenerating the metal ion-dependent DNAzyme to realize multiple enzymatic turnovers. Benefiting from target recycling, nanoparticle amplification, and catalytic and molecular beacon amplification, there is substantial amplification and the target miRNAs can be detected at 0.06 fM (miRNA-21) and 0.048 fM (miRNA-141) in a single assay. Furthermore, the high selectivity and accuracy of the assay were proved by practical analysis of different cancer cells, which exhibited good practicability in multiplex miRNA detection in clinical sera. The results indicate that the proposed strategy holds great potential for the sensitive detection of multiplex cancer biomarkers and offers the opportunity for future applications in clinical diagnosis.

catena-Poly[[trimethyl-tin(IV)]-µ-2-(2-chloro-phenyl)-acetato].

In the title polymeric coordination compound, [Sn(CH(3))(3)(C(8)H(6)ClO(2))](n), the Sn atoms exhibit a distorted trigonal-bipyramidal geometry with the carboxyl-ate O atoms of the 2-chloro-phenyl-acetato ligands in axial positions and with the equatorial sites occupied by the three methyl groups. Adjacent Sn atoms are bridged by coordination to the two O atoms of each 2-chloro-phenyl-acetato ligand, forming a chain structure.

Bis(2-amino-4-chloro-benzoato)triphenyl-anti-mony(V).

The title complex mol-ecule, [Sb(C(6)H(5))(3)(C(7)H(5)ClNO(2))(2)], possesses crystallographically imposed C(2) symmetry. The Sb atom exhibits a trigonal-bipyramidal geometry with the axial positions occupied by the O atoms of two carboxyl-ate groups and the equatorial positions by the C atoms of the phenyl groups. Intra-molecular N-H⋯O and C-H⋯O hydrogen bonds occur.

Bis(5-amino-2-chloro-benzoato-κO)triphenyl-anti-mony(V).

In the title compound, [Sb(C(6)H(5))(3)(C(7)H(5)ClNO(2))(2)], the Sb center has a distorted trigonal-bipyramidal geometry, with the O atoms of two carboxyl-ate groups in axial positions and the C atoms of the phenyl groups in equatorial positions. Intra-molecular C-H⋯O inter-actions occur. The mol-ecules are connected by inter-molecular N-H⋯O, N-H⋯N and C-H⋯O hydrogen-bonding inter-actions and C-H⋯π stacking inter-actions, forming a three-dimensional supra-molecular framework.

3,3'-Oxybi[isobenzofuran-1(3H)-one].

The title compound, C(16)H(10)O(5), consists of two isobenzofuran-1(3H)-one moieties which are linked by a bridging O atom. The two halves of the mol-ecule display approximate non-crystallographic mirror symmetry. The dihedral angle between the two isobenzofuran-1(3H)-one ring systems is 53.18 (6) Å. Two chiral carbon centres are observed in the compound, but their absolute configurations could not be determined. In the crystal structure, inter-molecular C-H⋯O hydrogen bonds link mol-ecules into zigzag chains along c. Additional C-H⋯O inter-actions connect adjacent chains.

(E)-2-(Isonicotinoylhydrazonometh-yl)benzoic acid methanol monosolvate.

The title compound, C(14)H(11)N(3)O(3)·CH(4)O, was synthesized by the condensation reaction of isonicotinohydrazide with an equimolar quantity of 2-formyl-benzoic acid in methanol. The hydrazone mol-ecule displays an E configuration about the C=N bond. The dihedral angel between the pyridine and the benzene rings is 12.04 (5)°. In the crystal structure, mol-ecules are linked by O-H⋯N, O-H⋯O and N-H⋯O hydrogen-bonding inter-actions.

3-[(3-Oxo-1,3-dihydro-isobenzofuran-1-yl)amino]benzoic acid.

In the title compound, C(15)H(11)NO(4), the dihedral angle formed by the benzene ring and isobenzofuran ring system is 67.82 (5) Å. The crystal structure is stabilized by inter-molecular O-H⋯O and N-H⋯O hydrogen-bonding inter-actions.

3-Eth-oxy-2-(1,3-thia-zol-2-yl)isoindolin-1-one.

In the title compound, C(13)H(12)N(2)O(2)S, the dihedral angles between the isoindolone ring system and the thia-zole ring and the eth-oxy group are 6.50 (11) and 89.0 (2)°, respectively.

Octa-butyl-bis{(E)-2-[4-(2-hydroxy-benzyl-ideneamino)phen-yl]acetato}di-µ(2)-methoxo-di-µ(3)-oxido-tetra-tin(IV).

The title compound, [Sn(4)(C(4)H(9))(8)(C(15)H(12)NO(3))(2)(CH(3)O)(2)O(2)], is a centrosymmetric dimer and displays a ladder type structural motif. There are four Sn(IV) centres which can be divided into two sorts, viz. two endocyclic and two exocyclic. The endo- and exocyclic Sn(IV) centres are linked by bidentate deprotonated methanol and µ(3)-O atoms. Each exocyclic Sn(IV) centre is also coordinated by a monodentate 2-[4-(2-hydroxy-benzyl-idene-amino)phen-yl]acetate ligand. Parts of the butyl groups were found to be disordered over two sets of sites.

Bis(2-hydroxy-benzaldehyde oximato-κO)triphenyl-anti-mony(V).

The mol-ecule of the title compound, [Sb(C(6)H(5))(3)(C(7)H(6)NO(2))(2)], is located on a twofold axis defined by the metal center and two C atoms of a coordinated phenyl group. The Sb center has a slightly distorted trigonal-bipyramidal geometry, with the axial positions occupied by the O atoms of symmetry-related 2-hydroxy-benzaldehyde oximate ligands. An intra-molecular O-H⋯N inter-action is present. The crystal structure is stabilized by C-H⋯O inter-actions.

[2-Oxido-1-naphthaldehyde (2-hydroxy-benzo-yl)hydrazonato]diphenyl-tin(IV).

In the title compound, [Sn(C(6)H(5))(2)(C(18)H(12)N(2)O(3))], the Sn(IV) atom has a distorted trigonal-bipyramidal geometry. The Schiff base mol-ecule is coordinated to the Sn(IV) atom in a tridentate fashion via the azomethine N atom, the hydr-oxy O atom and the carbonyl O atom. The complex involves an intra-molecular O-H⋯N hydrogen bond.

N'-[(E)-3-Pyridylmethyl-idene]benzo-hydrazide.

The title compound, C(13)H(11)N(3)O, was prepared by the reaction of benzohydrazide and nicotinaldehyde. The dihedral angle between the planes of the two aromatic rings is 47.78 (9)°. The crystal structure is stabilized by inter-molecular N-H⋯N hydrogen-bonding inter-actions.

(E)-2-Meth-oxy-6-(thia-zol-2-ylimino-meth-yl)phenol.

The title compound, C(11)H(10)N(2)O(2)S, displays an E configuration about the C=N bond. The mean planes of the thia-zole and benzene rings make a dihedral angle of 9.32 (18)°. Intra-molecular O-H⋯N hydrogen bonds are found in the crystal structure.

Dichloridoocta-kis(2-chloro-benz-yl)di-µ(2)-hydroxido-di-µ(3)-oxido-tetra-tin(IV).

The title tetra-nuclear Sn(IV) compound, [Sn(4)(C(7)H(6)Cl)(8)Cl(2)O(2)(OH)(2)], has site symmetry . Two O(2-) and two OH(-) anions bridge four Sn(IV) cations to form the tetra-nuclear compound. The two independent Sn(IV) cations assume SnO(3)C(2) and SnO(2)C(2)Cl distorted trigonal-bipyramidal coordination geometries. Intra-molecular O-H⋯Cl hydrogen bonding is present in the structure. One Cl atom of a chloro-benzyl ligand is disordered over two sites with an occupancy ratio of 0.693 (2):0.307 (2).

Fluorescence-enhanced p19 proteins-conjugated single quantum dot with multiplex antenna for one-step, specific and sensitive miRNAs detection.

Ideal methods for miRNA detection should be rapid and amplification-free in the mix-and-measure format. Here we report a novel FRET strategy based on fluorescence-enhanced p19 proteins-conjugated single quantum dot (QD) with multiplex antenna for one-step, specific and sensitive miRNAs quantitative analysis. It is simple in design and operation, and possesses high sensitivity and selectivity. In the strategy, RNA-binding viral p19 proteins-conjugated quantum dot (p19-QD) with high fluorescence and multiplex antenna was designed, and exploited for the capture recognition element and the donor. In the presence of target miRNAs, the p19-QD would tightly capture the miRNA-21-antimiRNA-21 duplex (dsRNA) formed in solution by hybridization of the specific antimiRNA-21-Cy3 probe (receptor) to the single-stranded miRNA-21 target. The FRET detection system between QD and Cy3 was constructed, and the signal read-out was measured. Conversely, in the absence of target miRNA-21, the p19-QD refuse to capture the free single-stranded antimiRNA-21-Cy3 probe (receptor), the FRET between quantum dot and Cy3 is deterred, thereby providing a low-background signal to improve sensitivity. Benefiting from the high affinity and specificity of p19 protein for duplex RNA and the fluorescence enhancement of donor p19-QD by the passivation and protection from p19 protein, a detection limit as low as 0.6 fM was achieved without employing any amplification techniques and pre-concentration or purification steps. The performance can be achieved by only one-step incubation without additional reagents and washing steps, thus greatly reducing the operating difficulty and saving time. Moreover, the fluorescence-enhanced p19-QD conjugate-based FRET strategy avoids the specific design in the number of the bases for interval in the DNA-QD conjugate-based FRET system using DNA strands as the FRET linker, and improves the FRET efficiency. Furthermore, it has been successfully applied to analyze the content of miRNA-21 in breast cancer cell. The results indicated that, the strategy will become a sensitive and reliable miRNAs quantification method in biomedical research and early clinical diagnostics.

Triphenyl-bis(2,4,5-trifluoro-3-methoxy-benzoato)anti-mony(V).

In the title compound, [Sb(C(6)H(5))(3)(C(8)H(4)F(3)O(3))(2)], the Sb atom lies on an inversion centre and exhibits a trigonal bipyramidal geometry with the axial positions occupied by the O atoms of two carboxyl-ate groups and the equatorial positions occupied by C atoms of the phenyl groups. Intra-molecular C-H⋯O hydrogen bonds stabilize the mol-ecular conformation. In the crystal structure, mol-ecules are connected by inter-molecular C-H⋯O hydrogen-bonding inter-actions, forming a layer structure parallel to (01).

catena-Poly[[trimethyl-tin(IV)]-µ-2,5-difluoro-benzoato-κO:O'].

In the title polymeric coordination compound, [Sn(CH(3))(3)(C(7)H(3)F(2)O(2))](n), the Sn atom exhibits a distorted trigonal-bipyramidal coordination geometry with the carboxyl-ate O atoms in the axial positions and the equatorial positions occupied by the methyl groups. The two Sn-O bond lengths are 2.225 (5) and 2.410 (6) Å.

catena-Poly[[trimethyl-tin(IV)]-µ-2,4,6-trichloro-benzoato].

In the title compound, [Sn(CH(3))(3)(C(7)H(2)Cl(3)O(2))](n), the tin(IV) atom exhibits a slightly distorted trigonal-bipyramidal geometry with two O atoms of symmetry-related carboxyl-ate groups in the axial positions and three methyl groups in the equatorial positions. In the crystal structure, the metal atoms are linked by carboxyl-ate bridges into polymeric chains extending along the b axis.