Imprinting Technology for Effective Sorbent Fabrication: Current State-of-Art and Future Prospects

In the last 10 years, we have witnessed an extensive development of instrumental techniques in analytical methods for determination of various molecules and ions at very low concentrations. Nevertheless, the presence of interfering components of complex samples hampered the applicability of new analytical strategies. Thus, additional sample pre-treatment steps were proposed to overcome the problem. Solid sorbents were used for clean-up samples but insufficient selectivity of commercial materials limited their utility. Here, the application of molecularly imprinted polymers (MIPs) or ion-imprinted polymers (IIPs) in the separation processes have recently attracted attention due to their many advantages, such as high selectivity, robustness, and low costs of the fabrication process. Bulk or monoliths, microspheres and core-shell materials, magnetically susceptible and stir-bar imprinted materials are applicable to different modes of solid-phase extraction to determine target analytes and ions in a very complex environment such as blood, urine, soil, or food. The capability to perform a specific separation of enantiomers is a substantial advantage in clinical analysis. The ion-imprinted sorbents gained interest in trace analysis of pollutants in environmental samples. In this review, the current synthetic approaches for the preparation of MIPs and IIPs are comprehensively discussed together with a detailed characterization of respective materials. Furthermore, the use of sorbents in environmental, food, and biomedical analyses will be emphasized to point out current limits and highlight the future prospects for further development in the field.     

基于“肝常有余”理论探讨化肝煎治疗儿童慢性咳嗽思路

[目的]基于“肝常有余”理论,探讨化肝煎治疗儿童慢性咳嗽思路。[方法]通过查阅中医古籍和现代文献资料,并结合临床实践经验,从“肝常有余”理论与儿童的生理、病理联系着手,探讨儿童慢性咳嗽的病因病机、症状特点和论治规律,并阐释化肝煎的来源、方义及其在儿童慢性咳嗽中的应用,并附验案一则加以佐证。[结果]“肝常有余”理论分别阐述了儿童的生理和病理特点,生理上的“有余”体现了小儿良好生长发育的生理机能状态;病理上的“有余”指生理上的“有余”可在各种因素作用下转化为病理上的“亢盛”表现,是小儿疾病向“易实”转化的病理基础。由此探索小儿慢性咳嗽的病因通常与感受外邪、饮食不适、情志不遂等因素有关,核心病机多为肝郁化火,木火刑金,症状特点多表现为春季多发、情志异常、夜间发作、病程日久,治疗本病的关键在于调肝,同时联合治肺诸法,以达肝肺同治。化肝煎的主要功用是疏肝解郁、降逆散火,符合小儿慢性咳嗽的核心病机特点,临证可加减使用。文末所举小儿慢性咳嗽医案辨证为肝郁化火、木火刑金证,治以疏肝泻火、化痰止咳为主,方用化肝煎加减取得了较好的临床疗效。[结论]“肝常有余”理论可用于指导儿童慢性咳嗽的治疗,运用化肝煎治...     

生物素在肿瘤靶向递药中的研究进展

运用靶向递药系统给药是目前治疗癌症的有效方法,靶向配体的选择是靶向递药的关键。生物素受体在多数肿瘤细胞表面过表达,但在正常细胞中低表达或不表达,因此,生物素可作为配体与药物载体相连,用于肿瘤靶向递药。简述生物素及生物素受体,综述生物素修饰的脂质体、胶束、纳米粒等载药系统在肿瘤靶向诊断和治疗中的研究进展,以期为相关研究开发与临床应用提供参考。     

mRNA技术在疫苗领域的探索与实践

mRNA疫苗是将编码抗原的mRNA递送到人体细胞内,在细胞内翻译后产生相应的抗原蛋白,从而诱导机体产生有效的免疫反应。与传统疫苗相比,mRNA疫苗安全性好、研发周期短、免疫效力高,可以同时刺激细胞免疫反应和体液免疫反应。随着核苷酸修饰技术和递送技术的发展,mRNA疫苗也迎来了广阔的应用前景。本文对mRNA技术及其在疫苗领域的应用进行综述,以期为正在或即将开展mRNA疫苗研发工作的学者提供理论和实践指导。

     

Limitations and caveats of magnetic cell labeling using transfection agent complexed iron oxide nanoparticles

Cell labeling with various types of nanomaterial, such as FDA‐approved iron oxide nanoparticles (IONPs) has become common practice in biomedical research. The low uptake of IONPs stimulates the use of transfection agents (TA), but the effect on stability of the IONPs and their cellular interactions has received minimal attention. In the present study, we evaluated the use of Lipofectamine as a commonly used TA and tested different ratios of TA and IONPs. While the TA–IONP complexes are stable in saline, at a high ratio of TA over IONP, substantial aggregation occurred in serum‐containing media. Even for the highest ratio, TA was unable to completely cover the IONPs, resulting in a net negative charge of all complexes. At high TA–IONP ratios, more complexes remained surface‐associated without internalization, resulting in cell death, while at lower TA–IONP ratios, complexes were more avidly taken up through fluid‐phase pinocytosis and clathrin‐mediated endocytosis. At later time points, the endocytosed complexes accumulated within the lysosomes and affected the appearance of lysosomal structures. The data indicate that TAs should be used with care as, depending on the ratio of TA and IONP, the complexes may aggregate, inducing cell death and preventing internalization. Copyright © 2012 John Wiley & Sons, Ltd.     

Exposure assessment of carbon nanotube manufacturing workplaces

Seven CNT (carbon nanotube) handling workplaces were investigated for exposure assessment. Personal sampling, area sampling, and real-time monitoring using an SMPS (scanning mobility particle sizer), dust monitor, and aethalometer were performed to characterize the mass exposure, particle size distribution, and particle number exposure. No workplace was found to exceed the current ACGIH (American Conference of Governmental Industrial Hygienists) TLVs (threshold limit values) and OELs (occupational exposure levels) set by the Korean Ministry of Labor for carbon black (3.5?mg/m³), PNOS (particles not otherwise specified; 3?mg/m³), and asbestos (0.1 fiber/cc). Nanoparticles and fine particles were most frequently released after opening the CVD (chemical vapor deposition) cover, followed by catalyst preparation. Other work processes that prompted nanoparticle release included spraying, CNT preparation, ultrasonic dispersion, wafer heating, and opening the water bath cover. All these operation processes could be effectively controlled with the implementation of exposure mitigation, such as engineering control, except at one workplace where only natural ventilation was used.     

Milk derived colloid as a novel drug delivery carrier for breast cancer

Triple negative breast cancer has an extremely poor prognosis when chemotherapy is no longer effective. To overcome drug resistance, novel drug delivery systems based on nanoparticles have had remarkable success. We produced a novel nanoparticle component ‘MDC’ from milk-derived colloid. In order to evaluate the anti-cancer effect of MDC, we conducted in vitro and in vivo experiments on cancer cell lines and a primary tumor derived breast xenograft. Doxorubicin (Dox) conjugated to MDC (MDC-Dox) showed higher cancer cell growth inhibition than MDC alone especially in cell lines with high EGFR expression. In a mouse melanoma model, MDC-Dox significantly suppressed tumor growth when compared with free Dox. Moreover, in a primary tumor derived breast xenograft, one of the mice treated with MDC-Dox showed partial regression, while mice treated with free Dox failed to show any suppression of tumor growth. We have shown that a novel nanoparticle compound made of simple milk-derived colloid has the capability for drug conjugation, and serves as a tumor-specific carrier of anti-cancer drugs. Further research on its safety and ability to carry various anti-cancer drugs into multiple drug-resistant primary breast models is warranted.     

Novel electrochemical xanthine biosensor based on chitosan–polypyrrole–gold nanoparticles hybrid bio-nanocomposite platform

The aim of this study was the electrochemical detection of the adenosine-3-phosphate degradation product, xanthine, using a new xanthine biosensor based on a hybrid bio-nanocomposite platform which has been successfully employed in the evaluation of meat freshness. In the design of the amperometric xanthine biosensor, chitosan–polypyrrole–gold nanoparticles fabricated by an in situ chemical synthesis method on a glassy carbon electrode surface was used to enhance electron transfer and to provide good enzyme affinity. Electrochemical studies were carried out by the modified electrode with immobilized xanthine oxidase on it, after which the biosensor was tested to ascertain the optimization parameters. The Biosensor exhibited a very good linear range of 1–200 μM, low detection limit of 0.25 μM, average response time of 8 seconds, and was not prone to significant interference from uric acid, ascorbic acid, glucose, and sodium benzoate. The resulting bio-nanocomposite xanthine biosensor was tested with fish, beef, and chicken real-sample measurements.     

Cell Death by Polyvinylpyrrolidine-Coated Silver Nanoparticles is Mediated by ROS-Dependent Signaling

Silver nanoparticles (AgNPs) are widely used nanoparticles and they are mainly used in antibacterial and personal care products. In this study, we evaluated the effect of AgNPs on cell death induction in the murine dendritic cell line DC2.4. DC2.4 cells exposed to AgNPs showed a marked decrease in cell viability and an induction of lactate dehydrogenase (LDH) leakage in a time- and dose-dependent manner. In addition, AgNPs promoted reactive oxygen species (ROS)-dependent apoptosis and AgNP-induced ROS triggered a decrease in mitochondrial membrane potential. The activation of the intracellular signal transduction pathway was also observed in cells cultured with AgNPs. Taken together, our data demonstrate that AgNPs are able to induce a cytotoxic effect in DCs through ROS generation. This study provides important information about the safety of AgNPs that may help in guiding the development of nanotechnology applications.