A novel dual-signal output strategy for POCT of CEA based on a smartphone electrochemical aptasensing platform.

A smartphone-based electrochemical aptasensing platform was developed for the point-of-care testing (POCT) of carcinoembryonic antigen (CEA) based on the ferrocene (Fc) and PdPt@PCN-224 dual-signal labeled strategy. The prepared PdPt@PCN-224 nanocomposite showed a strong catalytic property for the reduction of H2O2. Phosphate group-labeled aptamer could capture PdPt@PCN-224 by Zr-O-P bonds to form PdPt@PCN-224-P-Apt. Therefore, a dual signal labeled probe was formed by the hybridization between Fc-DNA and PdPt@PCN-224-P-Apt. The presence of CEA forced PdPt@PCN-224-P-Apt to leave the electrode surface due to the specific affinity, leading to the decrease of the reduction current of H2O2. At the same time, the Fc-DNA strand changed to hairpin structure, which made Fc closer to the electrode and resulted in the increase of the oxidation current of Fc. Thus, CEA can be accurately determined through both signals: the decrease of H2O2 reduction current and the increase of Fc oxidation current, which could avoid the false positive signal. Under the optimal conditions, the prepared aptasensor exhibited a wide linear range from 1 pg·mL-1 to 100 ng·mL-1 and low detection limits of 0.98 pg·mL-1 and 0.27 pg·mL-1 with Fc and PdPt@PCN-224 as signal labels, respectively. The aptasensor developed in this study has successfully demonstrated its capability to detect CEA in real human serum samples. These findings suggest that the proposed sensing platform will hold great potential for clinical tumor diagnosis and monitoring.

Surface hydrophobization of zeolite enables mass transfer matching in gas-liquid-solid three-phase hydrogenation under ambient pressure.

Attaining high hydrogenation performance under mild conditions, especially at ambient pressure, remains a considerable challenge due to the difficulty in achieving efficient mass transfer at the gas-liquid-solid three-phase interface. Here, we present a zeolite nanoreactor with joint gas-solid-liquid interfaces for boosting H2 gas and substrates to involve reactions. Specifically, the Pt active sites are encapsulated within zeolite crystals, followed by modifying the external zeolite surface with organosilanes. The silane sheath with aerophilic/hydrophobic properties can promote the diffusion of H2 and the mass transfer of reactant/product molecules. In aqueous solutions, the gaseous H2 molecules can rapidly diffuse into the zeolite channels, thereby augmenting H2 concentration surround Pt sites. Simultaneously, the silane sheath with lipophilicity nature promotes the enrichment of the aldehydes/ketones on the catalyst and facilitates the hydrophilia products of alcohol rediffusion back to the aqueous phase. By modifying the wettability of the catalyst, the hydrogenation of aldehydes/ketones can be operated in water at ambient H2 pressure, resulting in a noteworthy turnover frequency up to 92.3 h-1 and a 4.3-fold increase in reaction rate compared to the unmodified catalyst.

A smartphone-based electrochemical POCT for CEA based on signal amplification of Zr6MOFs.

Carcinoembryonic antigen (CEA) is a biomarker of high expression in cancer cells. Highly sensitive and selective detection of CEA holds significant clinical value in the diagnosis, monitoring and efficacy evaluation of malignant tumors. In this work, a smartphone-based electrochemical point-of-care testing (POCT) platform for the detection of CEA was developed based on a Zr6MOF signal amplification strategy. Ferrocene labeled DNA strands (Fc-DNA) were immobilized on Zr6MOFs to form a Fc-DNA/Zr6MOF signal probe. Double-stranded DNA (dsDNA) formed by complementary DNA (cDNA) and CEA aptamer was assembled on a screen-printed electrode via an Au-S bond. When CEA was added, the aptamer specifically bound with CEA, resulting in the exposure of cDNA. Then, Fc-DNA/Zr6MOF signal probes were introduced on the electrode surface through hybridization between Fc-DNA and cDNA. The detection of CEA was realized by measuring the electrochemical response of Fc. The POCT device was made by connecting a modified electrode with a smartphone through a Sensit Smart USB flash disk. Due to the signal amplification of Zr6MOFs, this POCT platform exhibited high sensitivity, wide linear range, and low detection limit for CEA detection. The developed POCT platform has been used for the detection of CEA in actual human serum samples with satisfactory results.

Ru-catalyzed C-H activation/cyclization of oximes with sulfoxonium ylides to access isoquinolines.

An external oxidant free Ru(II)-catalyzed C-H activation followed by an intermolecular annulation between oximes and sulfoxonium ylides has been developed. This transformation proceeds smoothly with a broad range of substrates, affording a series of isoquinoline derivatives in moderate to good yields. This protocol was successfully applied to the synthesis of moxaverine.

A label-free electrochemical aptasensor based on Bi-Sb alloy materials for potential POCT of HER-2.

As a prognostic biomarker for breast cancer, human epidermal growth factor receptor 2 (HER-2) is of crucial diagnostic value. Here, a label-free electrochemical aptasensor was established for the ultrasensitive detection of HER-2 using a modified electrode of Bi-Sb alloy materials (Bi-Sb AMs). The performance of the aptasensor was enhanced greatly due to the introduction of Bi-Sb alloy materials (Bi-Sb AMs) with high conductivity. Furthermore, by integrating the aptasensor with the Sensit Smart U-disk electrochemical analyzer, the point-of-care testing (POCT) for HER-2 was realized. Under the optimal experimental parameters, the POCT analyzer showed a wide linear response from 0.01 pg mL-1 to 100 ng mL-1, with a low detection limit (LOD) of 5.96 fg mL-1 for the detection of HER-2. The presented POCT analyzer exhibited good specificity, stability, and reproducibility. Benefiting from the simple operation and rapid testing, the developed analyzer will have potential application in the prognostic diagnosis and treatment of breast cancer.

Interfacial Reaction-Directed Green Synthesis of CeO2-MnO2 Catalysts for Imine Production through Oxidative Coupling of Alcohols and Amines.

Direct oxidative coupling of alcohols with amines over cheap but efficient catalysts is a promising choice for imine formation. In this study, porous CeO2-MnO2 binary oxides were prepared via an interfacial reaction between Ce2(SO4)3 and KMnO4 at room temperature without any additives. The as-prepared porous CeO2-MnO2 catalyst has a higher fraction of Ce3+, Mn3+, and Mn4+ and contains larger surface area and more oxygen vacancies. During the oxidative coupling reaction of alcohol with amine to imine, the as-obtained CeO2-MnO2 catalyst is motivated by the above encouraging characteristics and exhibits superior catalytic activity (98% conversion and 97% selectivity) and can also work effectively under a wide scope of temperatures and substrates. The in-depth in situ DRIFTS and density functional theory (DFT) results demonstrate that there is a strong interaction between CeO2 and MnO2 in the CeO2-MnO2 catalyst, exhibiting especially a positive synergistic effect in the direct coupling of alcohol and amine reaction.

Isoindolinone synthesis through Rh/Cu-catalyzed oxidative C-H/N-H annulation of N-methoxy benzamides with saturated ketones.

The synthesis of isoindolinones from N-methoxy benzamides and saturated ketones via a bimetallic tandem catalytic annulation has been accomplished. The reaction is catalyzed by a Rh/Cu-cocatalytic system and proceeds via the combination of Cu-catalyzed dehydrogenation of ketones and Rh-catalyzed direct C-H functionalization with the assistance of the N-methoxy amide group which also acts as an oxidant to regenerate the Rh catalyst. This method shows good compatibility with a wide range of substrates and functional groups, and provides an alternative strategy to obtain diverse isoindolinones.

Ag-Cu copromoted direct C2-H bond thiolation of azoles with Bunte salts as sulfur sources.

A direct C2-H thiolation of azoles with Bunte salts was achieved under the combined action of copper and silver salts. This protocol could furnish various substituted 2-thioazoles in moderate to good yields. This method has a broad substrate scope and shows good functional group tolerance.

Tandem Catalysis of Ammonia Borane Dehydrogenation and Phenylacetylene Hydrogenation Catalyzed by CeO2 Nanotube/Pd@MIL-53(Al).

Heterogeneously catalyzed, selective hydrogenation in the liquid phase is widely used in industry for the synthesis of chemicals. However, it can be a challenge to prevent active nanoparticles (e.g., palladium) from aggregation/leaching and meanwhile achieve high conversion as well as selectivity, especially under mild conditions. To address these issues, a CeO2 nanotube/Pd@MIL-53(Al) sandwich-structured catalyst has been prepared in which the MIL-53(Al) porous shell can efficiently stabilize the palladium nanoparticles. When this catalyst was used in a tandem catalytic reaction involving the dehydrogenation of ammonia borane and the hydrogenation of phenylacetylene, remarkably, the hydrogen released from the dehydrogenation of ammonia borane boosted the catalytic process, with 100 % conversion of phenylacetylene and a selectivity of 96.2 % for styrene, even at room temperature and atmospheric pressure, within 1 min. This work therefore provides an alternative strategy for balancing the conversion and selectivity of liquid-phase hydrogenation reactions.

Co(ii)/Cu(ii)-cocatalyzed oxidative C-H/N-H functionalization of benzamides with ketones: a facile route to isoindolin-1-ones.

A cobalt and copper catalyzed reaction protocol has been developed to achieve the oxidative C-H/N-H annulation of benzamides containing an 8-aminoquinoline moiety as the directing group with ketones. Structurally diverse isoindolin-1-ones were furnished by the reaction of various substituent benzamides with ketones.

A simple route towards the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles from primary amines and 1,3-dicarbonyl compounds under metal-free conditions.

An acetic acid-promoted approach that enables the synthesis of 1,4,5-trisubstituted 1,2,3-triazole derivatives has been achieved. This transformation employs readily available primary amines, 1,3-dicarbonyls and tosyl azide as the starting materials via a cycloaddition reaction under metal-free conditions. The reaction provides a simple access to fully substituted 1,2,3-triazoles from commercial substrates in moderate to excellent yields.

The Ag-promoted α-C-H arylation of alcohols.

We herein report the functionalization of α-C-H in alcohols through cross-dehydrogenative coupling reactions. Selectfluor was used as a mild oxidant. In situ-generated HF participated in the reaction and no external strong acid was necessary. A variety of heteroaryl-substituted alcohols were achieved with good yields and with good functional group tolerance.

Visible light-promoted difluoromethylthiolation of aryldiazonium salts.

Difluoromethylthiolation of aryldiazonium salts under photocatalytic conditions with a shelf-stable, easily prepared and inexpensive reagent, PhSO2SCF2H was described. A variety of difluoromethylthioethers were obtained utilizing aryldiazonium salts containing different functional groups. Aryldiazonium salts with a heteroarene moiety were tolerated. Fluorescence quenching experiments indicated that both oxidative and reductive quenching cycles occurred during this process.

Rhodium(III)-Catalyzed C(sp3)-H Bond Aminocarbonylation with Isocyanates.

Rh(III)-catalyzed C(sp3)-H bond aminocarbonylation of 8-methylquinolines and isocyanates has been realized under mild conditions. This approach is applicable to different aryl and alkyl isocyanates, leading to the synthesis of various α-quinolinyl amide compounds in moderate to excellent yields. A plausible mechanism for this transformation is proposed according to the experimental results obtained.

A Foldamer-Based Organocatalyst for Direct Arylations of Unactivated Arenes.

It was demonstrated that a simple yet well-folded pyridone dimer, possessing two convergently aligned electron-rich O atoms for potassium binding, can serve as a highly efficient organocatalyst for catalyzing transition-metal-free arylations of unactivated aromatic C-H bonds with aryl halides in the presence of t-BuOK. A wide range of aryl iodides could be cross-coupled with unactivated arenes in moderate to excellent yields. The experiments using radical-scavenging reagents confirm the participation of radicals in this catalytic transformation.

Rh(III) -Catalyzed C-H Olefination of Benzoic Acids under Mild Conditions using Oxygen as the Sole Oxidant.

Phthalide skeletons have been synthesized for the first time through a Rh(III) -catalyzed C-H olefination of benzoic acids under mild conditions using oxygen as the sole oxidant. Aromatic acids bearing a variety of functional groups could react with diverse alkenes to afford the desired cyclized lactones or uncyclized alkenylarenes in moderate-to-excellent yields.

Ambient-Temperature Ortho C-H Arylation of Benzoic Acids with Aryl Iodides with Ligand-Supported Palladium Catalyst.

The ambient-temperature ortho C-H arylation of electron-deficient benzoic acids with aryl iodides has been achieved by using an Ac-Ile-OH-supported Pd catalyst. A wide range of unactivated benzoic acids could cross-couple an array of aryl iodides in moderate to excellent yields. The choice of HFIP as a solvent is crucial to realizing the mild C-H arylation, and the beneficial effect of the ligand on the reaction likely stems from the accelerated C-H activation process and the improved catalyst lifetime.

Carboxylic acids as traceless directing groups for the rhodium(III)-catalyzed decarboxylative C-H arylation of thiophenes.

A rhodium(III)-catalyzed carboxylic acid directed decarboxylative C-H/C-H cross-coupling of carboxylic acids with thiophenes has been developed. With a slight adjustment of the reaction conditions based on the nature of the substrates, aryl carboxylic acids with a variety of substituents could serve as suitable coupling partners, and a broad variety of functional groups were tolerated. This method provides straightforward access to biaryl scaffolds with diverse substitution patterns, many of which have conventionally been synthesized through lengthy synthetic sequences. An illustrative example is the one-step gram-scale synthesis of a biologically active 3,5-substituted 2-arylthiophene by way of the current method.

Proton gradient-induced water transport mediated by water wires inside narrow aquapores of aquafoldamer molecules.

Hollow tubular aquapores inside aquafoldamers can be created via the "sticky" end-mediated formation of 1D chiral helical stacks involving same-handed helices, and are capable of aligning H-bonded water molecules in a chain-like fashion. These aquapores uniquely feature a small cavity of ∼2.8 Šin diameter, a size identical to that of the water molecule and also comparable to the narrowest opening in naturally occurring aquaporins measuring ∼3 Šacross, and hence allow not only proton transport but also unique proton-gradient-induced water transport across the lipid membranes in the presence of proton gradient.