Stable Molecular Diodes Based on π-π Interactions of the Molecular Frontier Orbitals with Graphene Electrodes.

In molecular electronics, it is important to control the strength of the molecule-electrode interaction to balance the trade-off between electronic coupling strength and broadening of the molecular frontier orbitals: too strong coupling results in severe broadening of the molecular orbitals while the molecular orbitals cannot follow the changes in the Fermi levels under applied bias when the coupling is too weak. Here, a platform based on graphene bottom electrodes to which molecules can bind via π-π interactions is reported. These interactions are strong enough to induce electronic function (rectification) while minimizing broadening of the molecular frontier orbitals.

DNA Labeling Generates a Unique Amplification Probe for Sensitive Photoelectrochemical Immunoassay of HIV-1 p24 Antigen.

Photoelectrochemical (PEC) immunoassay is an attractive methodology as it allows for an elegant and sensitive protein assay. However, advanced PEC immunoassay remains challenging and the established amplifications rely almost exclusively on the labeling of various enzymes, which usually suffer the inferior stabilities. Here we report the development and validation of the DNA labeling that leads to a unique amplification probe for the sensitive PEC immunoassay of HIV-1 capsid protein, p24 antigen, an important biomarker of human immune deficiency virus (HIV).

[Phenolic constituents of Ampelopsis grossedentata from zhangjiajie].

Objective: To study the phenolic constituents from Ampelopsis grossedentata.

Methods: Compounds were isolated using column chromatographic techniques (silica gel, polyamide gel, Sephadex LH-20) and semi-preparative HPLC. Structures were elucidated on the basis of spectral data (NMR and HR-MS).

[Content determination of two isomers containd in Garcinia hanburyi by HPLC].

Objective: To establish a method for determing the content of two isomers containd in Garcinia hanburyi by HPLC.

Method: Chromatographic column of SunFire (Waters) C8 (2.1 mm x 150 mm, 3.

[Determination of the total content of astragaloside IV in Radix Astragali].

Objective: To determine the total content of astragaloside IV in Radix Astragali.

Methods: The measurement conditions were used as follows: Irregular C18 (4.6 mm x 250 mm, 5 microm) column; mobile phase: acetonitrile-water (32:68); flow rate: 1.