RESUMO
Styrene-maleic acid (SMA) copolymer has received much attention for its excellent solubilization characteristics. In this work, SMA copolymer brush-based chromatographic stationary phases were exploited and developed for the first time. First, SMA copolymer brush was in situ grown on the surface of spherical silica via living/controlled reversible addition-fragmentation chain transfer (RAFT) polymerization method. Subsequently, as a proof-of-concept demonstration, the copolymer was esterified by diethylene glycol mono-2-ethylhexyl ether (DGME) and 2-(2-ethylhexyloxy) ethanol (EHOE), respectively. The obtained Sil-SMA-DGME and Sil-SMA-EHOE copolymer-brush chromatographic stationary phases were characterized by transmission electron microscopy, Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, and thermogravimetric analysis, respectively. The chromatographic retention mechanism indicated that both the two packed columns exhibited hydrophilic/reverse mixed-mode retention modes. The maximum column efficiency was up to 71,000 N/m. The chromatographic separation performance evaluation indicated that the novel kind of stationary phases had excellent separation capabilities for hydrophilic, hydrophobic compounds and phospholipid standards. In addition, by combination with mass spectrometry identification, the Sil-SMA-DGME column was further exploited for separation and identification of phospholipids in human lung cancer cells. Totally, 9 classes including 186 phospholipid species were successfully identified. The results demonstrated the promising application prospects of the novel kind of SMA copolymer-brush chromatographic stationary phases.
RESUMO
PD-L1 is overexpressed on the surface of tumor cells and binds to PD-1, resulting in tumor immune escape. Therapeutic strategies to target the PD-1/PD-L1 pathway involve blocking the binding. Immune checkpoint inhibitors have limited efficacy against tumors because PD-L1 is also present in the cytoplasm. PD-L1 of post-translational modifications (PTMs) have uncovered numerous mechanisms contributing to carcinogenesis and have identified potential therapeutic targets. Therefore, small molecule inhibitors can block crucial carcinogenic signaling pathways, making them a potential therapeutic option. To better develop small molecule inhibitors, we have summarized the PTMs of PD-L1. This review discusses the regulatory mechanisms of small molecule inhibitors in carcinogenesis and explore their potential applications, proposing a novel approach for tumor immunotherapy based on PD-L1 PTM.
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RESUMO
The accurate determination of polar cationic pesticides in food poses a challenge due to their high polarity and trace levels in complex matrices. This study hypothesized that the use of halloysite nanotubes (HNTs) can significantly enhance the extraction efficiency and sensitivity of these analytes because of their rich hydroxyl groups and cation exchange sites. Therefore, we chemically incorporated HNTs with organic polymer monoliths for in-tube solid-phase microextraction (SPME). This novel hybrid monolith extended service life, improved adsorption capacity, and exhibited excellent extraction performance for polar cationic pesticides. Based on these advancements, a robust and sensitive in-tube SPME-HILIC-MS/MS method was constructed to determine trace levels of polar cationic pesticides in complex food matrices. The method achieved limits of detection of 1.9, 2.1, and 0.1 µg/kg for maleic hydrazide, amitrole, and cyromazine, respectively. The spiked recoveries in five food samples ranged from 80.2 to 100.8%, with relative standard deviations below 10.7%.
RESUMO
The pharmaceutical analysis course is a three-dimensional knowledge network that connects several courses to form a new comprehensive knowledge node involving a large knowledge system and flexible knowledge structure. In this course, the subject of chromatography covers a wide range of topics. However, because accurate content is challenging to present, the teaching effect of this subject is poor. In this work, we sought to achieve the educational purpose of establishing morality and cultivating talent, as well as the goal of training highly skilled professionals, by taking the teaching of chromatography in the pharmaceutical analysis course as an example of transforming scientific research results into teaching resources. The resources obtained are integrated into the teaching process to provide innovative and scientific research ideas to students with the aim of not only helping them understand and master technical knowledge but also exercise their ability to raise and solve problems. Furthermore, we expound on how to introduce scientific development frontiers and formulate scientific problems through curriculum design. We also describe how our strategy can promote the teaching effect and achieve teaching objectives. Based on the characteristics of rapid knowledge update and equal emphasis on theory and practice in pharmaceutical analysis, the course is designed by introducing new advances in scientific development, formulating scientific problems, and adopting question- and problem-based learning methods for teaching. The teaching effect is then evaluated through diversified assessment, student feedback, and self-evaluation. The results show that the transformation of scientific research results into teaching resources plays a significant role in stimulating students' interest in learning, improving students' ability to solve problems, and achieving curriculum objectives, all of which greatly improve the teaching effect.