A new sandwich-type electrochemiluminescence sensor based on HPSNs-NH2@Au NPs and AuPdPt NPs for determination of α(2,3)-sial-Gs.

A novel sandwich-type "on-off" electrochemiluminescence (ECL) biosensor for the determination of α(2,3)-sial-Gs was designed. Specifically, amino-functionalized porous silica nanoparticles (HPSNs-NH2) were first prepared and then decorated with gold nanoparticles (Au NPs) to form HPSNs-NH2@Au NP nanocomposite, which exhibited a strong ability to enhance ECL intensity with K2S2O8 as co-reactant (signal-on) and could immobilize the target-specific binding molecules of maackia amurensis lectin (MAL). Additionally, AuPdPt trimetallic nanoparticles were prepared to serve as a quenched ECL signal indicator (signal-off) with the ability of capturing the target non-specific binding molecules of 3-aminophenylboronic acid (APBA) to form a signal label. The sandwich-type ECL biosensor was constructed based on the structure of MAL-α(2,3)-sial-Gs-APBA and achieved a determination toward α(2,3)-sial-Gs with a wide linear range from 1 fg mL-1 to 10 ng mL-1 and a low detection limit of 0.5 fg mL-1. Furthermore, the proposed ECL biosensor showed satisfactory selectivity, stability, and reproducibility for α(2,3)-sial-Gs determination.

Dimeric Copper and Lithium Thiolates: Comparison of Copper Thiolates with Their Lithium Congeners.

The direct reactions of the large terphenyl thiols HSAriPr4 (AriPr4= -C6H3-2,6-(C6H3-2,6-iPr2)2) and HSAriPr6 (AriPr6= -C6H3-2,6-(C6H2-2,4,6-iPr3)2) with stoichiometric amounts of mesitylcopper(I) in THF at ca. 80 °C afforded the first well-characterized dimeric copper thiolato species {CuSAriPr4}2 (1) and {CuSAriPr6}2 (2) with elimination of mesitylene. The complexes 1 and 2 were characterized by NMR and electronic spectroscopy as well as by X-ray crystallography. They have dimeric Cu2S2 core structures in which the two copper atoms are bridged by the sulfurs from the thiolato ligands and feature short Cu--Cu distances near 2.4 Å as well as a weak copper-flanking aryl ring interaction from a terphenyl substituent. The structures of the planar Cu2S2 cores bear a resemblance to the CuA site in nitrous oxide reductase in which two cysteines also bridge two copper atoms. The related dimeric Li2S2 structural motif was also observed in the lithium congeners {LiSAriPr4}2 (3) and {LiSAriPr6}2 (4) which were synthesized directly from the thiols and n-BuLi in hexanes. However, despite the very similar effective ionic radii of the Li+ (0.59 Å) and Cu+ (0.60 Å) ions, the Li--Li structures display very much longer (by more than ca. 0.5 Å) separations than the corresponding Cu--Cu distances in 1 and 2, which may be due to weaker dispersion interactions.

Characterization of a Monomeric, Homoleptic, Solvent-Free Samarium Bis(aryloxide).

The reaction of Sm[N(SiMe3)2]2(THF)2 with 2 equiv of the bulky aryloxide ligand HOAr iPr6 [Ar iPr6 = -C6H3-2,6-(C6H2-2,4,6- iPr3)2] afforded the first monomeric homoleptic solvent-free bis(aryloxide) lanthanide complex Sm(OAr iPr6)2. The complex was characterized by crystallography and UV-visible and IR spectroscopy and magnetically by Evans' method. The O-Sm-O angle is highly bent at 111.08(9)°. The samarium ion in Sm(OAr iPr6)2 also displays close contacts with the flanking aryl rings of the terphenyloxide ligands. The complex is paramagnetic at room temperature with a magnetic moment of 3.51 µB.

A chitosan derivative/phytic acid polyelectrolyte complex endowing polyvinyl alcohol film with high barrier, flame-retardant, and antibacterial effects.

Films with high barrier, flame-retardant, and antibacterial properties are beneficial in terms of food and logistics safety. Herein, a polyelectrolyte complex (PEC) of N-(2-hydroxyl)-propyl-3-trimethylammonium chitosan chloride (HTCC, chitosan derivative) and phytic acid (PA) was successfully prepared and then incorporated into a polyvinyl alcohol (PVA) matrix to fabricate a composite film with satisfactory barrier, fire-retardant, and antibacterial properties. The influence of HTCC/PA (HTPA) on the structural, physical and functional properties of the PVA matrix was investigated. Compared with the PVA film, PVA-HTPA6 film exhibited 3.38 times of flexibility and 83.33 % and 80.64 % of water vapor permeability and oxygen permeability, respectively. Benefiting from HTPA, the PVA-HTPA6 film exhibited outstanding flame-retardant capacity, with a high LOI value (33.30 %) and immediate self-extinguishing behaviour. Furthermore, the HTPA endowed the films with excellent antibacterial properties. Compared with other films, the PVA-HTPA6 film effectively maintained the quality of pork during storage at 4 °C for 9 days. Our findings indicate that the films are promising for packaging and logistics safety with oil-containing foods.

Capillary-Assisted Monitoring of Milk Freshness via a Porous Cellulose-Based Label with High pH Sensitivity.

A cellulose-based matrix for monitoring milk freshness (MF) was produced from rice straw particles (RSPs) in a 0.125-0.150 mm that was bis-quaternized to attach bromocresol purple (BP) as a sensor. Under alkali conditions, the obstinate structure of the rice straw had opened, thereby improving the accessibility of the cellulose. Bis-quaternization created more adsorption sites for BP. The maximum adsorption capacity was 97.68 mg/g. The sensors were interwoven with cellulosic fibers to form the cellulose-based label with a relatively loose three-dimensional structure via hydrogen bonds. As the proportion of BP-BCRPs was increased from 10% to 40%, the air permeability of the label increased from 3.76 to 15.01 mm/s, which increased the response to the tested gases (10.12 s for 1 mL of acetic acid). The intelligent label exhibited excellent sensitivity at pH values of 3-9 with highly saturated color changes. During the storage period, the label color shifted from blue-purple to yellow as acidity was increased from 17.24 to 19.8 °T due to capillarity action, providing a timely warning to consumers. The prepared colorimetric porous intelligent cellulose-based label is suitable for monitoring of MF.

Hydrostannylation of carbon dioxide by a hydridostannylene molybdenum complex.

Reaction of the aryltin(II) hydrides {AriPr4Sn(µ-H)}2 or {AriPr6Sn(µ-H)}2 (AriPr4 = -C6H3-2,6-(C6H3-2,6-iPr2)2, AriPr6 = -C6H3-2,6-(C6H2-2,4,6-iPr3)2) with two equivalents of the molybdenum carbonyl [Mo(CO)5(THF)] afforded the divalent tin hydride transition metal complexes, Mo(CO)5{Sn(AriPr6)H}, (1), or Mo(CO)5{Sn(AriPr4)(THF)H} (2), respectively. Complex 1 effects the facile hydrostannylation of carbon dioxide, to yield Mo(CO)5{Sn(AriPr6)(κ2-O,O'-O2CH)}, (3), which features a bidentate formate ligand coordinating the tin atom. Reaction of 3 with the pinacolborane, HBpin (pin = pinacolato) in benzene regenerated 1 in quantitative yield. All complexes were characterized by X-ray crystallography, as well as UV-visible, IR, and multinuclear NMR spectroscopies. The isolation of 1 and 2 is consistent with the existence of monomeric forms of {AriPr4Sn(µ-H)}2 and {AriPr6Sn(µ-H)}2 in solution. Regeneration of 1 from 3via reaction with pinacolborane as the hydrogen source shows the catalytic potential of 1 in the hydrogenation of CO2.

The establishment of an immunosensor for the detection of SPOP.

In this paper, we first synthesis three-dimensional jasmine-like Cu@L-aspartic acid(L-ASP) inorganic-organic hybrid nanoflowers to load palladium-platinum nanoparticles (Pd-Pt NPs) as the signal enhancer in order to quantify intracellular speckle-type POZ domain protein. Scanning electron microscope, fourier transform infrared, energy dispersive spectrometer, X-ray photoelectron spectroscopy analysis was used to characterize the newly synthesized materials. The newly formed Cu@L-Asp/Pd-PtNPs can catalyze the decomposition of hydrogen peroxide and exhibit excellent catalytic performance. When different concentration of speckle-type POZ domain protein is captured by speckle-type POZ domain protein antibody linked to the surface of Cu@L-Asp/Pd-Pt NPs, the current signal decreases with the increase concentration of speckle-type POZ domain protein. After optimization, the speckle-type POZ domain protein immunosensor exhibited a good linear response over a concentration range from 0.1-1 ng mL-1 with a low detection limit of 19 fg mL-1. The proposed sensor demonstrates good stability within 28 days, acceptable reproducibility (RSD = 0.52%) and selectivity to the speckle-type POZ domain protein in the presence of possible interfering substances and has potential application for detecting other intracellular macromolecular substances.

Au@BSA microspheres-luminol and a novel luminescent Zeolitic Imidazolate Framework were used for potential-resolved electrochemiluminescence to detect dual targets.

Here, a novel electrochemiluminescence biosensor based on potential-resolved strategy was firstly prepared for the detection of dual targets α2,3-sialylated glycans and α2,6-sialylated glycans. This is the first time that Au@BSA microsphere was used to connect with luminol to enhance its ECL intensity, and it can generate ECL signals at positive potential. Zeolitic Imidazolate Framework-8 (ZIF-8) and Meso-tetra (4-carboxyphenyl) porphyrin (TCPP) were linked using a one-pot method to synthesize a novel luminescent ZIF (L-ZIF) named TZZ, which can emit ECL signals at negative potential. Moreover, magnetite microspheres were used to construct a sandwich-type biosensor to obtain higher sensitivity and reduce background signals. In addition, the biosensor manufactured directly in solution have a wider linear range than constructed on electrode because it has more available space than the electrode surface. Due to the above advantages, the prepared ECL biosensor exhibited high sensitivity, stability and broader linear range, even for practical analysis. Therefore, the prepared ECL biosensor will become a promising method for determination of α2,3-sialylated glycans and α2,6-sialylated glycans in clinical applications in the future. What is more, it provides a potential method for detection of other multi-targets.