Influence of Hydroxypropyl- β -Cyclodextrin on the Photostability of Fungicide Pyrimethanil

Pesticides continue to play an important role in pest management. However, the intensive pesticide application has triggered several environment negative effects that cannot be disregarded. In this study, the inclusion complex of pyrimethanil with HP- β -CD has been prepared and characterized by proton nuclear magnetic resonance spectroscopy. The formation of the pyrimethanil/HP- β -CD inclusion complex increased the aqueous solubility of this fungicide around five times. To assess the influence of microencapsulation on the environmental photostability of the fungicide, the photochemical degradation of pyrimethanil and pyrimethanil/HP- β -CD inclusion complex has been investigated in different aqueous media such as ultrapure and river water under simulated solar irradiation. The studies allow concluding that pyrimethanil/HP- β -CD inclusion complex increases significantly the photostability of the fungicide in aqueous solutions, especially in natural water. Actually, the half-life of pyrimethanil/HP- β -CD inclusion complex was increased approximately by a factor of four when compared to the free fungicide. The overall results point out that pyrimethanil can be successfully encapsulated by HP- β -CD, a process that can improve its solubility and photostability properties.

Multifunctional Biosensor Based on Localized Surface Plasmon Resonance for Monitoring Small Molecule–Protein Interaction

We report an optical sensor based on localized surface plasmon resonance (LSPR) to study small-molecule protein interaction combining high sensitivity refractive index sensing for quantitative binding information and subsequent conformation-sensitive plasmon-activated circular dichroism spectroscopy. The interaction of α-amylase and a small-size molecule (PGG, pentagalloyl glucose) was log concentration-dependent from 0.5 to 154 μM. In situ tests were additionally successfully applied to the analysis of real wine samples. These studies demonstrate that LSPR sensors to monitor small molecule–protein interactions in real time and in situ, which is a great advance within technological platforms for drug discovery.