Chitosan-coated polystyrene solid-phase extraction fillers.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 is a global health emergency. The main protease is an important drug target in coronaviruses. It plays an important role in the processing of viral RNA-translated polyproteins and is highly conserved in the amino acid sequence and three-dimensional structure, making it a good drug target for which several small molecule inhibitors are available. This paper describes the various anti-severe acute respiratory syndrome coronavirus 2 inhibitor drugs targeting Mpro discovered since the severe acute respiratory syndrome coronavirus 2 outbreak at the end of 2019, with all these compounds inhibiting severe acute respiratory syndrome coronavirus 2 Mpro activity in vitro. This provides a reference for the development of severe acute respiratory syndrome coronavirus 2 Mpro-targeted inhibitors and the design of therapeutic approaches to address newly emerged severe acute respiratory syndrome coronavirus 2 mutant strains with immune evasion capabilities.

Based on the specific binding of sulfonic acid groups to melamine, β-agonists and other compounds, Fe3O4 nano-magnetic beads were coated with polystyrene using an improved micro-suspension emulsion polymerization method, thus forming core–shell magnetic polystyrene microspheres (Fe3O4@PS) with Fe3O4 as the core and polystyrene as the shell. These functionalized microspheres, which can be used as magnetic solid-phase extraction (MSPE) adsorbent, were prepared after further sulfonation. These microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size analysis and saturation magnetization measurement. The results showed that these sulfonated magnetic polystyrene microspheres had favorable sphericity. The particle size of these microspheres ranged from 1μm to 10μm. Additionally, these microspheres had good dispersion and magnetic responses in both inorganic and organic solvents. Moreover, these functionalized magnetic polystyrene microspheres were tested and evaluated by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The results indicated that these sulfonated magnetic polystyrene microspheres (Fe3O4@SPS) could effectively adsorb such illegal additives as β-agonists and melamine in the food matrix.