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A new metal–organic aerogel (MOA-Rh-2) containing dirhodium paddle-wheels has been prepared from the reaction of dirhodium(ii) tetracarboxylate (Rh2(OAc)4) and tetrakis(4-carboxyphenyl)porphyrin (TCPP) in a mixed solvent of DMF and water, followed by supercritical CO2 extraction. MOA-Rh-2 has been fully characterized by ICP-OES, EDS, XPS, PXRD, SEM, TEM and TGA. Its porosity has been confirmed by N2 adsorption isotherms at 77 K, and the Barrett–Joyner–Halenda pore size is centered at 3.5 nm. The existence of mesopores has been further verified by dye adsorption tests using methylene blue (14.4 × 6.1 Å2) and rhodamine B (15.8 × 11.8 × 6.8 Å3). MOA-Rh-2 is air and moisture-stable. The catalytic results show that, under an air atmosphere and at ambient temperature, a low loading (0.1–0.4 mol%) of MOA-Rh-2 can efficiently promote the hydrosilylation of aldehydes and ketones with the commercially available silane of PhSiH3. After catalytic reactions, MOA-Rh-2 can be recycled and reused for 5 runs without significant loss of the activity, and the reaction conversions are in the range of 89–99%. [ABSTRACT FROM AUTHOR]

In this study, hyperbranched polyethyleneimine-protected silver nanoclusters (hPEI-AgNCs) with excellent electrochemiluminescence (ECL) emission in the presence of coreactant K2S2O8 were prepared by chemical reduction of silver ions (silver nitrate) coordinated with dendrigraft polymer, and successfully used for the construction of an ECL immunosensor. Polyaniline (PANI)/polypyrrole (PPy)-silver (Ag) dendrites with good electrical conductivity and biocompatibility were electropolymerized on the surface of indium tin oxide (ITO) electrode as carriers. Porous ZnO sphere-loaded hPEI-AgNCs-induced signal amplification strategies were integrated exquisitely and applied sufficiently. Taking carcinoembryonic antigen (CEA) as an example, under optimal conditions, the CEA concentration was determined to be in the range of 10−3 ng mL−1–100 ng mL−1 and with a detection limit of 0.4 pg mL−1 using this method; it exhibited excellent selectivity, high stability, and acceptable fabrication reproducibility. It was anticipated that hPEI-AgNCs would have promising applications in green, selective, and sensitive detection of target analytes in the future. [ABSTRACT FROM AUTHOR]

A dual functional analytical device performing both energy conversion and electric energy storage based on biofuel cells to implement self-powered point-of-care testing was developed based on a piece of Ti foil. [ABSTRACT FROM AUTHOR]

In this paper, a simple and sensitive sandwich-type photoelectrochemical (PEC) immunosensor for measurement of biomarkers on a gold nanoparticle-modified indium tin oxide (ITO) electrode through electrodeposition for point-of-care testing was developed by using a tin dioxide quantum dot–graphene nanocomposite (G–SnO2) as an excellent label with amplification techniques. The capture antibody (Ab1) was firstly immobilized on the gold nanoparticle-modified ITO electrode due to the covalent conjugation, then the antigen and the AuNP/PDDA–G–SnO2 nanocomposite nanoparticle labeled signal antibody (Ab2) were conjugated successively to form a sandwich-type immunocomplex through a specific interaction. Under irradiation with a common ultraviolet lamp (∼365 nm, price $50), the SnO2 NPs were excited and underwent charge-separation to yield electrons (e−) and holes (h+). As the holes were scavenged by ascorbic acid (AA), the electrons were transferred to the ITO electrode through RGO to generate a photocurrent. The photocurrents were proportional to the CEA concentrations, and the linear range of the developed immunosensor was from 0.005 to 10 ng mL−1 with a detection limit of 0.036 pg mL−1. The proposed sensor shows high sensitivity, stability, reproducibility, and can become a promising platform for other biomolecular detection. [ABSTRACT FROM AUTHOR]

The sequence-specific detection of DNA hybridization has attracted considerable interest in numerous fields. Although traditional DNA biosensors have been widely explored due to their high sensitivity, it is still challenging to develop a low-cost, portable, disposable, fast, and easy-to-use DNA detection method for public use at home or in the field. To address these challenges, herein, we report a novel microfluidic photoelectrochemical (PEC) paper-based analytical platform, integrated with an internal chemiluminescent light source, a novel paper supercapacitor (PS) amplifier, and a terminal digital multi-meter (DMM) detector, for sensitive DNA detection using a graphene-modified porous Au-paper electrode as the working electrode to obtain enhanced PEC responses. The quantification mechanism of this strategy is based on the charging of this PS, which was constructed on a paper-based analytical platform through a simple “drawing and soaking” method, by the generated photocurrent. After a fixed period, the PS was automatically shorted under the control of a novel built-in fluidic delay-switch to output an instantaneously amplified current, which could be sensitively detected by the DMM. At optimal conditions, this paper-based analytical platform can detect DNA at concentrations at femtomolar level. This approach also shows excellent specificity toward single nucleotide mismatches. [ABSTRACT FROM AUTHOR]

A stable and porous porphyrinic metal–organic framework, Ru-PMOF-1(Hf), has been prepared through the self-assembly of [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato](monocarbonyl)ruthenium (Ru(TCPP)(CO)) and HfCl4. Single-crystal X-ray diffraction analysis reveals that Ru-PMOF-1(Hf) possesses a three-dimensional (3D) structure with orthogonal 1D open channels of 1.9 × 1.9 nm2. The porous nature has been confirmed by gas adsorption measurements. Its catalytic activity for the carbene insertion into N–H bonds has been investigated. The catalytic results indicate that Ru-PMOF-1(Hf) is efficient for the insertion reactions of ethyl 2-diazoacetate (EDA) into a range of secondary amines with up to 92% yield, 938 TON and 2475 h−1 TOF. As an excellent heterogeneous catalyst, Ru-PMOF-1(Hf) can be recovered and reused for at least ten runs with negligible loss of catalytic activity. Due to its uniform microporosity in three orthogonal directions, Ru-PMOF-1(Hf), of which the particle sizes were carefully controlled by sieving, can induce size selectivity regarding the amine substrates. The reactivities of different unbranched dialkylamines, such as diethylamine (NHEt2), dibutylamine (NHBu2) and dipentylamine (NHPent2), have been compared, and the results display an apparent decreasing trend along the chain lengthening. For comparison, the corresponding nonporous and homogeneous catalyst Ru(TMCPP)(CO) (TMCPP = tetrakis(4-methoxycarbonylphenyl)porphyrin) displays negligible difference towards the reactions with these three amines. [ABSTRACT FROM AUTHOR]

Self-assembly of a new metalloporphyrin tetracarboxylic ligand Ir(TCPP)Cl (TCPP = tetrakis(4-carboxyphenyl)porphyrin) with ZrCl4 in the presence of benzoic acid leads to the formation of a three-dimensional (3D) iridium(iii)-porphyrin metal–organic framework (Ir-PMOF) with the formula of [(Zr6(μ3-O)8(OH)2(H2O)10)2(Ir(TCPP)Cl)3]·solvents (Ir-PMOF-1(Zr)), which possesses square-shaped channels of 1.9 × 1.9 nm2 (atom-to-atom distances across opposite Ir metal atoms) in three orthogonal directions as disclosed by the single-crystal X-ray diffraction analysis. Ir-PMOF-1(Zr) represents the first MOF bearing a self-supporting iridium-porphyrin catalytic framework, featuring high porosity and stability. The catalytic tests disclose that the activated Ir-PMOF-1(Zr) can promote O–H insertion with a turnover frequency (TOF) up to 4260 h−1. Ir-PMOF-1(Zr) can be recycled and reused for 10 runs without significant loss of catalytic activity, and the total turnover number (TON) for O–H insertion after 10 successive runs reaches 875. [ABSTRACT FROM AUTHOR]