Preparation and chromatographic performance of chiral peptide-based stationary phases for enantiomeric separation.

This study presents the development of three new chiral stationary phases. They are based on silica modified with peptides containing phenylalanine and proline. Successful analyses and characterizations were conducted using Fourier transform infrared spectra, elemental analysis, and thermogravimetric analysis. After this, the enantioselective performance of the three chiral peptide-based columns was evaluated. The evaluation used 11 racemic compounds under normal-phase high performance liquid chromatography mode. Optimized enantiomeric separation conditions were established. Under these conditions, the enantiomers of flurbiprofen and naproxen were successfully separated on CSP-1 column: the separation factor of these was 1.27 and 1.21, respectively. In addition, the reproducibility of the CSP-1 column was also investigated. The results of the investigation illustrated that the stationary phases have good reproducibility (RSD = 0.73%, n = 5).

Label-Free Small Extracellular Vesicles Capturing Strategy for Lung Cancer Diagnosis and Typing Based on a Natural Polyphenol-Metal Three-Dimensional Network.

Small extracellular vesicles (sEVs) have been increasingly recognized as circulating biomarkers and prognosticators for disease diagnosis. However, the clinical applications of sEVs are seriously limited by the lack of a robust and easy scale-up isolation technique. Herein, the feasibility of a polyphenol-metal three-dimensional (3D) network for label-free sEV isolation was explored. As a proof-of-concept, with tannic acid (TA) as the polyphenolic ligand and Fe(III) as the coordinated metal, the TA-Fe(III) 3D network coating mesoporous silica beads (SiO2@BSA@Fe-TA6) was designed and fabricated via a coordination-driven layer-by-layer self-assembly approach. The successful fabrication of SiO2@BSA@Fe-TA6 was validated by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. With the low-cost TA (as low as US$ 0.18/g) as the probe, SiO2@BSA@Fe-TA6 achieved universal capture toward sEVs in different cells and plasma samples. The capture efficiency reached 85.4 ± 1.5%, which is comparable to the antibody-based capture techniques and significantly higher than the ultracentrifugation (UC) method. The purity of sEVs isolated by SiO2@BSA@Fe-TA6 from the H1299 cell culture supernatant was measured as (1.07 ± 0.14) × 1011 particles/µg, which is 3.1 times higher than that via the UC method. Another important superiority of SiO2@BSA@Fe-TA6 is the facile self-assembly approach, which can harvest a yield of up to grams, allowing simultaneous processing of more than 500 plasma samples. The SiO2@BSA@Fe-TA6-based strategy was further successfully employed to distinguish nonsmall cell lung cancer (NSCLC) and small cell lung cancer (SCLC) with an accuracy of 87.1%. The developed SiO2@BSA@Fe-TA6 is a label-free, universal, low cost, and easy scale-up technique for sEV-based liquid biopsy in lung cancer diagnosis and typing.

Propofol Attenuates Isoflurane-Induced Neurotoxicity and Cognitive Impairment in Fetal and Offspring Mice.

BACKGROUND: Anesthesia in pregnant rodents causes neurotoxicity in fetal and offspring rodents. However, the underlying mechanisms and targeted treatments remain largely to be determined. Isoflurane and propofol are among commonly used anesthetics. Thus, we set out to investigate whether propofol can mitigate the isoflurane-induced neurotoxicity in mice. METHODS: Pregnant C57BL/6 mice at gestational day 15 (G15) were randomly assigned to 4 groups: control, isoflurane, propofol, and isoflurane plus propofol. Levels of interleukin (IL)-6 and poly-ADP ribose polymerase (PARP) fragment were measured in the brains of G15 embryos, and levels of postsynaptic density (PSD)-95 and synaptophysin were determined in the hippocampal tissues of postnatal day 31 (P31) offspring using Western blotting and immunohistochemical staining. Learning and memory functions in P31 offspring were determined using a Morris water maze test. RESULTS: Isoflurane anesthesia in pregnant mice at G15 significantly increased brain IL-6 (222.6% ± 36.45% vs 100.5% ± 3.43%, P < .0001) and PARP fragment (384.2% ± 50.87% vs 99.59% ± 3.25%, P < .0001) levels in fetal mice and reduced brain PSD-95 (30.76% ± 2.03% vs 100.8% ± 2.25%, P < .0001) and synaptophysin levels in cornu ammonis (CA) 1 region (57.08% ± 4.90% vs 100.6% ± 2.20%, P < .0001) and dentate gyrus (DG; 56.47% ± 3.76% vs 99.76% ± 1.09%, P < .0001) in P31 offspring. Isoflurane anesthesia also impaired cognitive function in offspring at P31. Propofol significantly mitigated isoflurane-induced increases in brain IL-6 (117.5% ± 10.37% vs 222.6% ± 36.45%, P < .0001) and PARP fragment (205.1% ± 35.99% vs 384.2% ± 50.87%, P < .0001) levels in fetal mice, as well as reductions in PSD-95 (49.79% ± 3.43% vs 30.76% ± 2.03%, P < .0001) and synaptophysin levels in CA1 region (85.57% ± 2.97% vs 57.08% ± 4.90%, P < .0001) and DG (85.05% ± 1.87% vs 56.47% ± 3.76%, P < .0001) in hippocampus of P31 offspring. Finally, propofol attenuated isoflurane-induced cognitive impairment in offspring. CONCLUSIONS: These findings suggest that gestational isoflurane exposure in mice induces neuroinflammation and apoptosis in embryos and causes cognitive impairment in offspring. Propofol can attenuate these isoflurane-induced detrimental effects.

[Modified styrene-maleic anhydride copolymer-based chromatographic stationary phase for phospholipid separation and analysis].

Phospholipids are important signaling molecules, and their metabolism is closely related to various diseases, such as neurodegenerative diseases and cancers. Phospholipids are typically characterized with extreme complexity and structural diversity. For example, phospholipids present in many different forms, such as sn position isomers, double-bond position isomers, double-bond stereochemical isomers, and enantiomers. Therefore, further research on novel separation and analytical techniques for phospholipids is of great importance. As an amphiphilic alternating copolymer, styrene-maleic anhydride copolymer (SMA) can be inserted into the phospholipid bilayer of biofilms to form lipid nanodisks with membrane proteins as the centers, thereby solubilizing membrane proteins and phospholipids. Thus, the introduction of SMA into a chromatographic stationary phase can potentially improve the separation and analysis of phospholipids. In this paper, SMA was successfully grafted onto the surface of silica gel via the "click" reaction and free radical polymerization. After further ring-opening modification of SMA with methyl methionine hydrochloride (MME·HCl), a novel SMA-modified stationary phase material (Sil-SMA-MME) was fabricated. The Sil-SMA-MME stationary phase was characterized using thermogravimetric analysis and Fourier transform infrared spectroscopy (FT-IR), and the results indicated the successful fabrication of the target material. The retention mechanism of the packed Sil-SMA-MME chromatographic column was investigated using hydrophilic nucleosides and nucleic acid bases via high performance liquid chromatography (HPLC) and UV detection. According to the retention characteristics of the nucleosides and nucleic acid bases in different mobile phases, the Sil-SMA-MME chromatographic column exhibited a typical hydrophilic-interaction-based retention mechanism, similar to that of a commercially available amino (SiO2-NH2) column. The separation performance of the Sil-SMA-MME column was evaluated using three types of small-molecule substances, including amides, nucleoside/nucleic acid bases, and phenols. Cyanoacetamide, 2-iodoacetamide, benzamide, p-aminobenzamide, and nicotinamide were used to evaluate the chromatographic performance of the developed Sil-SMA-MME column. When acetonitrile-H2O (96∶4, v/v) was used as the mobile phase, the five compounds exhibited good peak shapes and could be baseline-separated within 8 min. The highest column efficiency achieved was 90900 N/m. By contrast, under the same chromatographic conditions, the test substances were not separated effectively on the SiO2-NH2 column. Regardless of the mobile phase ratio, the peaks of benzamide and 2-iodoacetamide overlapped. These results demonstrate that the developed Sil-SMA-MME column has good separation selectivity. The separation performance of the Sil-SMA-MME column for phospholipid samples was also investigated by HPLC and evaporative light scattering detection (ELSD) to explore its feasibility for phospholipid separation and analysis. Different phospholipid standards were used to evaluate the separation performance of the column. Under certain mobile phase conditions, baseline separation could be achieved for dipalmityl phosphatidyl serine sodium (DPPS), diolyl phosphatidyl choline (DOPC), and dipalmityl phosphatidyl ethanolamine (DPPE), as well as four phosphatidyl choline (PC) standards, namely, lysophosphatidylcholine (LysoPC), dimyristoyl phosphatidyl choline (DMPC), distearyl phosphatidyl choline (DSPC), and dipalmitoyl phosphatidyl choline (DPPC). The separation potential of the developed Sil-SMA-MME column was further evaluated by separating and analyzing phospholipid extracts from Antarctic krill oil and human serum. The results showed that the developed Sil-SMA-MME column has good potential for phospholipid separation and analysis.

Polymerized phosphonium ionic liquid functionalized silica microspheres as mixed-mode stationary phase for liquid chromatographic separation of phospholipids.

There is a large and growing demand for the vigorous development of new high performance liquid chromatography stationary phases in order to solve complex phospholipids separation. Herein, phosphonium-based ionic liquid trioctyl(allyl)phosphonium bromide ([P888Allyl]Br) was first synthesized with trioctylphosphine and allyl bromide. With [P888Allyl]Br as the polymerizable monomer, polymerized phosphonium ionic liquid functionalized silica microsphere (PIL@SiO2) was further synthetized via click chemistry reaction. Significantly, based on the inherent amphiphilic nature of the introduced [P888Allyl]Br, the packed PIL@SiO2 column displayed hydrophilic/hydrophobic mixed-mode retention mechanisms. The PIL@SiO2 column can achieve separation of nucleic acid bases and nucleosides, sulfonamides, amides and anilines with excellent selectivity in a shorter separation time. The column efficiency reached 109,700 N/m for 2-iodoacetamide. One of the important characteristics of the PIL@SiO2 column is that both phospholipid classes and species can be efficiently separated via the same column, outperforming that of the commercial amino column. Furthermore, the application potential of the PIL@SiO2 column was further verified via separation of phospholipids extracted from soy lecithin. The proposed PIL@SiO2 column provides a promising candidate for separation of complex phospholipid samples.

Genetic Variants of the Receptor for Advanced Glycation End-products in Susceptibility to Type 2 Diabetes Mellitus in Primary Hypertensive Patients.

Diabetes mellitus is frequently comorbid with hypertension, which is approximately twice as common as diabetes mellitus in China. We designed a case-control association study to inspect the susceptibility of the receptor for advanced glycation end-products (RAGE) gene 6 variants to type 2 diabetes mellitus (T2DM) in 2199 patients with primary hypertension (1252 diabetic cases and 947 nondiabetic controls). The genotypes/alleles of -429T > C and 82Gly > Ser variants differed significantly between the two groups, and their associations with T2DM were significant after Bonferroni correction. Two variants, -374T > A and I/D, showed only marginal associations with T2DM. Haplotype analysis of above 4 significant variants indicated that a low-penetrance haplotype simultaneously bearing -429C and 82Ser alleles was overrepresented in cases relative to controls (4.75% vs. 1.72%, P < 0.001). Moreover, the predictive capability of 6 variants was significantly superior to available risk factors, with better goodness-of-fit. A predictive nomogram of 4 baseline risk factors and 2 variants of statistical significance was structured, with a good predictive accuracy (C-index = 0.761, P < 0.001). Taken together, our findings highlighted a contributory role of the RAGE gene, especially its two functional variants -429T > C and 82Gly > Ser, in susceptibility to T2DM in primary hypertensive patients, which may aid early detection and risk assessment for high-risk individuals.