Single-Atom Co─O Sites Embedded in a Defective-Rich Porous Carbon Layer for Efficient HO Electrosynthesis.

The production of hydrogen peroxide (HO) via the two-electron electrochemical oxygen reduction reaction (2e ORR) is an essential alteration in the current anthraquinone-based method. Herein, a single-atom Co─O electrocatalyst is embedded in a defective and porous graphene-like carbon layer (Co─O@PC). The Co─O@PC electrocatalyst shows promising potential in HO electrosynthesis via 2e ORR, providing a high HO selectivity of 98.

Sensitive detection of Escherichia coli in diverse foodstuffs by electrochemical aptasensor based on 2D porphyrin-based COF.

The two-dimensional porphyrin-based covalent organic framework (denoted by Tph-TDC-COF) was used as the sensitive layerto build an aptamer-based electrochemical sensor for the detection of Escherichia coli (E.coli). Tph-TDC-COF produced with 5,10,15,20-tetrakis(4-aminophenyl)-21H, 23H-porphine (Tph) and [2,2'-bithiophene]-2,5'-dicarbaldehyde (TDC) as building blocks exhibited a highly conjugated structure, outstanding conductivity, large specific surface area, and strong bioaffinity towards aptamers.

Multiple active cobalt species embedded in microporous nitrogen-doped carbon network for the selective production of hydrogen peroxide.

To obtain excellent electrocatalysts for improving HO yield and selectivity, we formulated a novel method for embedding cobalt catalytic active sites in porous two-dimensional nitrogen-doped carbon network (CN) network and employed them as excellent two-electron oxygen reduction reaction (2e-ORR) electrocatalysts. The polymeric cobalt-based metal-organic framework (polyCo-MOF) and melamine-cyanuric acid-complex (MCA) hybrid (denoted as polyCo-MOF@MCA) was used as a precursor for preparing a series of electrocatalysts comprising multiple active sites such as metallic Co, CoO, or Co-N, which are homogeneously embedded in the porous two-dimensional CN network through pyrolysis at high temperatures (600 °C, 700 °C, and 800 °C) under N atmosphere. The obtained CoO/Co@CN hybrid by pyrolyzing polyCo-MOF@MCA at 700 °C displayed remarkably high HO production and large selectivity in an alkaline solution.

Hierarchical CoCoPBA@PCN-221 nanostructure for the highly sensitive detection of deoxynivalenol in foodstuffs.

An electrochemical impedimetric immunosensor was constructed based on a hierarchical nanostructured CoCo Prussian blue analogue entrapped by a Zr-based porphyrin MOF (denoted by CoCoPBA@PCN-221) for the sensitive detection of deoxynivalenol (DON). Given that CoCoPBA@PCN-221 demonstrated a hierarchical nanostructure, large specific surface area, and the synergistic effect between mixed metal valence states (Co/Co) and Zr clusters, it thus displayed a high binding interaction with the DON-targeted antibody. Compared with CoCoPBA and PCN-221, CoCoPBA@PCN-221 showed a superior stabilization ability toward the antibody-antigen complex in aqueous solution.

Impedimetric aptasensor based on porphyrin-based covalent-organic framework for determination of diethylstilbestrol.

An impedimetric sensing strategy was developed for sensitively determining diethylstilbestrol (DES) based on a platform of porphyrin-containing covalent-organic framework (p-COF). The p-COF was synthesized using 5,10,15,20-tetra (4-aminophenyl) porphyrin (TAPP) and 1,3,6,8-tetrakis(4-formylphenyl) pyrene (TFPy) as building blocks via condensation reaction, for which p-COF was named as TAPP-TFPy-COF. Considering the large specific surface area (302.

Construction of bifunctional electrochemical biosensors for the sensitive detection of the SARS-CoV-2 N-gene based on porphyrin porous organic polymers.

In this study, a novel porphyrin-based porous organic polymer (POP) was constructed using 5,10,15,20-tetramine (4-aminophenyl) porphyrin (TAPP) and 5,5'-diformyl-2,2'-bipyridine (DPDD) as organic ligands a solvothermal method (represented as TAPP-DPDD-POP). Then, it was utilized as a bifunctional scaffold for constructing a sensitive sensing strategy toward the nucleocapsid phosphoprotein (N-gene) of SARS-CoV-2. The obtained TAPP-DPDD-POP is composed of nanospheres with a size of 100-300 nm and possesses a highly conjugated and π-π stacking network.

Surface plasmon resonance aptasensor based on niobium carbide MXene quantum dots for nucleocapsid of SARS-CoV-2 detection.

A novel label-free surface plasmon resonance (SPR) aptasensor has been constructed for the detection of N-gene of SARS-CoV-2 by using thiol-modified niobium carbide MXene quantum dots (NbC-SH QDs) as the bioplatform for anchoring N-gene-targeted aptamer. In the presence of SARS-CoV-2 N-gene, the immobilized aptamer strands changed their conformation to specifically bind with N-gene. It thus increased the contact area or enlarged the distance between aptamer and the SPR chip, resulting in a change of the SPR signal irradiated by the laser (He-Ne) with the wavelength (λ) of 633 nm.

Porphyrin-based covalent organic framework as bioplatfrom for detection of vascular endothelial growth factor 165 through fluorescence resonance energy transfer.

A fluorescent aptasensor based on porphyrin-based covalent organic framework (p-COF) and carbon dots (CDs) was constructed for detecting vascular endothelial growth factor 165 (VEGF) and for imaging of the breast cancer cell line Michigan cancer foundation-7 (MCF-7). CDs synthesized with strong photoluminescence at λ∼380 nm were used as donors to label the VEGF-targeted aptamers (Apt/CDs). Additionally, the p-COF nanostructure comprised rich functional groups of CN on the surface and π-stacking planar nanostructure, resulting in the CDs adsorption via weakly π-π stacking, hydrogen bond and the Van der Waals force.