茶多酚锰-壳聚糖微球的制备、控释和诱导肝癌细胞凋亡的研究

选用壳聚糖为微米粒包被材料, 制备茶多酚锰(Tea Polyphenol Manganese, TPMn)-壳聚糖微球. 用荧光显微技术研究了TPMn-壳聚糖微球的荧光特性, 用扫描和透射电子显微镜证实TPMn-壳聚糖微球尺寸和分布规律. RP-HPLC定量分析TPMn-壳聚糖微球包封率为68%, 符合微米级微粒控释药物包封率的要求. 动力学研究结果表明, 茶多酚(TP)-壳聚糖和TPMn-壳聚糖的微球均有控释TP的能力, 控释时间高达40 h以上, 但前者释放速率稍快于后者. TPMn和TPMn-壳聚糖微球均能诱导肝癌细胞凋亡, 但TPMn-壳聚糖微球诱导肿瘤细胞的凋亡速率稍高于TPM. 实验结果证实, 以TPMn-壳聚糖微球方式控释TPMn有利于提高诱导肿瘤细胞凋亡速率. TPMn-壳聚糖微球具有研发成注射型抗肿瘤新药的可能性.     

Continuous flow microfluidic cell inactivation with the use of insulating micropillars for multiple electroporation zones

Electroporation is a powerful tool for inactivating cells and transfecting biological cells and has applications in biology, genetic engineering, medicine, environment, and many others. We report a new continuous flow device embedded with insulating micropillars to achieve better performance of cell inactivation. The use of micropillars creates multiple electroporation zones with enhanced local electric field strengths. Using a model solution of Saccharomyces cerevisiae, we examined the inactivation performance of the device under various applied electric voltages and flow rates. Results from the numerical simulations and experiments showed that even with an induced transmembrane potential of 0.58 V, close to 63% of cell inactivation was achieved at a flow rate of 2.5 mL/h. This was higher than the 24% cell inactivation observed for a reference device without micropillars that was subjected to the same conditions.     

Highly green fluorescent Nb2C MXene quantum dots for Cu2+ ion sensing and cell imaging

Niobium carbide MXene quantum dots (Nb₂C MQDs) derived from 2D Nb₂CT_x (MXene) are the rising-star material recently. Herein, a sulfur and nitrogen co-doped Nb₂C MQDs (S, N-MQDs) were synthesized through a hydrothermal method. The obtained Nb₂C MQDs have excellent green fluorescence with a quantum yield (QY) of 17.25%. In addition, they exhibited excitation-dependent photoluminescence, anti-photobleaching and dispersion stability. They emit light at 520 nm when excited at 390 nm. The Nb₂C MQDs could be successfully applied to copper ion detection with detection limit of 2 μmol/L and Caco-2 cells imaging.     

Stimuli Induced Uptake of Protein-Like Peptide Brush Polymers

Recently, we presented a strategy for packaging peptides as side-chains in high-density brush polymers. For this globular protein-like polymer (PLP) formulation, therapeutic peptides were shown to resist proteolytic degradation, enter cells efficiently and maintain biological function. In this paper, we establish the role charge plays in dictating the cellular uptake of these peptide formulations, finding that peptides with a net positive charge will enter cells when polymerized, while those formed from anionic or neutral peptides remain outside of cells. Given these findings, we explored whether cellular uptake could be selectively induced by a stimulus. In our design, a cationic peptide is appended to a sequence of charge-neutralizing anionic amino acids through stimuli-responsive cleavable linkers. As a proof-of-concept study, we tested this strategy with two different classes of stimuli, exogenous UV light and an enzyme (a matrix metalloproteinase) associated with the inflammatory response. The key finding is that these materials enter cells only when acted upon by the stimulus. This approach makes it possible to achieve delivery of the polymers, therapeutic peptides or an appended cargo into cells in response to an appropriate stimulus.     

Microscopic characterization of tension wood cell walls of Japanese beech (Fagus crenata) treated with ionic liquids

Tension wood that is an abnormal part formed in angiosperms has been barely used for wood industry. In this study, to utilize the tension wood effectively by means of liquefaction using ionic liquid, we performed morphological and topochemical determination of the changes in tension wood of Japanese beech (Fagus crenata) during ionic liquid treatment at the cellular level using light microscopy, scanning electron microscopy and confocal Raman microscopy. Ionic liquid treatment induced cell wall swelling in tension wood. Changes in the tissue morphology treated with ionic liquids were different between normal wood and tension wood, moreover the types of ionic liquids. The ionic liquid 1-ethyl-3-methylimidazolium chloride liquefied gelatinous layers rapidly, whereas 1-ethylpyridinium bromide liquefied slowly but delignified selectively. These novel insights into the deconstruction behavior of tension wood cell walls during ionic liquid treatment provide better understanding of the liquefaction mechanism. The obtained knowledge will contribute to development of an effective chemical processing of tension wood using ionic liquids and lead to efficient use of wood resources.     

Meta-analysis of gene expression for development and validation of a diagnostic biomarker panel for Oral Squamous Cell Carcinoma

We use a newly developed feature extraction and classification method to analyze previously published gene expression data sets in Oral Squamous Cell Carcinoma and in healthy oral mucosa in order to find a gene set sufficient for diagnoses. The feature selection technology is based on the relative dichotomy power concept published by us earlier. The resulting biomarker panel has 100% sensitivity and 95% specificity, is enriched in genes associated with oncogenesis and invasive tumor growth, and, unlike marker panels devised in earlier studies, shows concordance with previously published marker genes.     

Recent Advances and Developments of in vitro Evaluation of Heterocyclic Moieties on Cancer Cell Lines

Besides worthy development in cancer therapy, cancer is still one of the leading causes of death, worldwide. The future burden of cancer will probably be even larger because people are adopting poor lifestyles with poor diet, frequently smoking and less physical activity. The effective anticancer drugs having efficacy and selectivity with low toxicity is still a challenge for the scientific fraternity. The advances in the cancer study have its origin on the availability of different types of experimental model systems that review the various forms of this disease. Cell lines emerge as a feasible alternative for anticancer activities, being at the same time easy to manipulate and molecularly characterize. Heterocycles are key structural components of many of the anti‐cancer drugs available on the market today. Indeed, of the novel molecular anti‐cancer agents approved by the FDA between 2010 and 2017, almost two‐thirds contained heterocyclic rings within their structures. This review summarizes and provides updated literature on heterocyclic compounds using various cancer cell lines reported during the period of 2014–2017 together with the structure‐activity relationships.     

SCOUT: A new algorithm for the inference of pseudo-time trajectory using single-cell data

Single cell technology is a powerful tool to reveal intercellular heterogeneity and discover cellular developmental processes. When analyzing the complexity of cellular dynamics and variability, it is important to construct a pseudo-time trajectory using single-cell expression data to reflect the process of cellular development. Although a number of computational and statistical methods have been developed recently for single-cell analysis, more effective and efficient methods are still strongly needed. In this work we propose a new method named SCOUT for the inference of single-cell pseudo-time ordering with bifurcation trajectories. We first propose to use the fixed-radius near neighbors algorithms based on cell densities to find landmarks to represent the cell states, and employ the minimum spanning tree (MST) to determine the developmental branches. We then propose to use the projection of Apollonian circle or a weighted distance to determine the pseudo-time trajectories of single cells. The proposed algorithm is applied to one synthetic and two realistic single-cell datasets (including single-branching and multi-branching trajectories) and the cellular developmental dynamics is recovered successfully. Compared with other popular methods, numerical results show that our proposed method is able to generate more robust and accurate pseudo-time trajectories. The code of the method is implemented in Python and available at https://github.com/statway/SCOUT.     

Synthesis and in vitro biological evaluations of novel tetrapeptide as therapeutic agent for wound treatment

We report a new small peptide containing four amino acid residues (glycine-aspartic acid-proline-histidine) conjugated with palmitic acid (Palmitoyl-GDPH) that was synthesized, characterized and evaluated for its biological activities. The Palmitoyl-GDPH was prepared by solid phase peptide synthesis (SPPS) with high percentage purity of 98.6%. The results of circular dichroism (CD) demonstrated the feasibility and stability of Palmitoyl-GDPH secondary structure at many temperatures up to 60 °C. Palmitoyl-GDPH showed its greatest collagenase inhibition activity and nitric oxide (NO) scavenging effect of 80.00 ± 2.22% at 1.0 mg/ml and 83.40 ± 8.08% at 2.5 mg/ml, respectively. In addition, in-vitro cell based study revealed that Palmitoyl-GDPH was not toxic and possessed strong proliferative activity towards normal human dermal fibroblast (NHDF) cell line. Wound scratch assay method showed that Palmitoyl-GDPH significantly promoted the cell migration which progressed faster compared to tetracycline-treated group (positive control) by about 98.39 ± 2.79% and 95.79 ± 3.83%, respectively. Collectively, these results suggested that newly synthesized Palmitoyl-GDPH possessed a strong candidate for use as therapeutic agent and can be a novel approach in the treatment of cutaneous wounds.     

正极添加Na2WO4对镍氢电池高温性能的影响

研究了添加不同比例的Na2WO4对镍正极高温性能的影响, 结果表明, Na2WO4可提高镍氢电池的高温充电效率. 70 ℃条件下, 添加1.0%(w)的Na2WO4时镍正极的充电效率达到85%以上. 此外, Na2WO4的加入也可提高镍氢电池的放电容量、循环寿命和荷电保持率. 研究表明: Na2WO4可以促进镍正极高温下充电正反应的进行, 提高析氧过电位.