Simultaneous label-free screening of G-quadruplex active ligands from natural medicine via a microfluidic chip electrophoresis-based energy transfer multi-biosensor strategy.

Rapid screening of active compounds plays a crucial role in the research and application of complex natural medicines. Herein, a new method of simultaneous label-free multi-drug screening based on a selective aptamer-carboxyfluorescein/graphene oxide energy transfer optical sensor combined with microfluidic chip electrophoretic separation is reported. In this study, seven traditional Chinese medicinal monomers were chosen as targets for the screening of G-quadruplex ligands. The screening results of the G-quadruplex active ligands, including daidzein, berberine hydrochloride, jatrorrhizine hydrochloride, and fangchinoline, and non-active ligands, including geniposide and oxymatrine, were consistent with those reported in literature. Moreover, one new potential G4DNA active drug, jujuboside A, was identified. Molecular simulation of the interaction between G4DNA and drugs was also carried out using HyperChem and AutoDock to verify the results of the experimental screening. It further demonstrated the reliability of our strategy. This novel separation and concentration based multi-sensing strategy provides a simple, rapid, and sensitive tool for simultaneous multi-drug screening, which is very meaningful for drug screening and bio-interaction analysis.

Effect of ultrasound treatment on porcine myofibrillar protein binding furan flavor compounds at different salt concentrations.

The effects of ultrasound (500 W) on the interaction of porcine myofibrillar protein (MP) with furan flavor compounds at different salt concentrations (0.6 %, 1.2 % and 2.4 %) were investigated. With the increase of salt concentration, the particle size of MP decreased, and the surface hydrophobicity and active sulfhydryl content increased due to the unfolding and depolymerization of MP. At the same time, ultrasound promoted the exposure of hydrophobic binding sites and hydrogen bonding sites of MP in different salt concentration systems, thus improving the binding ability of MP with furan compounds by 2 % to 22 %, among which MP had the strongest binding capacity of 2-pentylfuran. In conclusion, ultrasound could effectively promote the unfolding of the secondary structure of MP, which was beneficial to the combination of MP and furan flavor compounds under different salt concentrations.

Ultrasound treatment enhanced the ability of the porcine myofibrillar protein to bind furan compounds: Investigation of underlying mechanisms.

This study was designed to explore the effects of different ultrasound power levels (0-600 W) on the ability of myofibrillar protein (MP) to bind furan compounds by analyzing the results of SDS-PAGE, particle size, Raman spectra, fluorescence intensity, solubility, turbidity, zeta potential, surface hydrophobicity, sulfhydryl content, solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). As ultrasound power levels were increased from 0 to 500 W, the hydrophobic bonding sites, hydrogen-bonding sites, and electrostatic effects increased due to the unfolding and depolymerization of MP, thus enhancing the ability of MP to bind furan (flavor-enhancing) compounds. Consistent with these results, the positive effect of ultrasound resulted in ability of MP to bind furan compounds increased by 19.00 % to 33.32 %. However, after 600-W ultrasound treatment, the MP aggregated again and the bonding sites were re-embedded, which decreased the furan-binding ability.