Adsorption of a cationic water-soluble dye onto cationic Langmuir–Blodgett films via nano clay platelets: An efficient approach to control the H-dimer

This communication reports the successful adsorption of a water-soluble cationic fluorescent dye Acridine Orange (AO) onto Langmuir–Blodgett (LB) films of a cationic amphiphile octadecylamine (ODA) in the presence of nano-clay platelets hectorite. Acridine orange (AO) has been widely used as a stainer for the characterization of biopolymers. But AO has a tendency to form non-florescent H-dimer even in the aqueous solution. Anionic nano-clay platelets hectorite played an important role in controlling the H-dimer formation of AO in the hybrid film. Effects of various parameters in the adsorption process were investigated in detail.     

单个血小板的拉曼光谱分析

利用波长为785 nm的激光束构建光镊拉曼光谱系统,俘获悬浮在生理盐水中的人和三种动物(家猪、大鼠、家兔)的单个血小板,激发并收集其拉曼光谱。单个血小板的平均拉曼光谱信号清楚地反映了血小板的生化组成特点,人血小板的拉曼光谱与三种动物的明显不同,1 524 cm-1是人类血小板所特有的拉曼信号峰,而1 157 cm-1在人类中显著高于三种动物的,人类血小板的平均I_{1 157}/ I_{1 003}为0.795,而家猪、大鼠、家兔的分别为0.532,0.502,0.485。多元统计分析结果显示,不同物种血小板的拉曼信号落入不同的空间,可以判别区分。上述结果表明,单个血小板的拉曼光谱基本反映了血小板的主要组成成分,结合多元统计分析可以用于辨别不同的物种的血小板,光镊拉曼光谱系统是实时研究细胞生理、生化变化的快速简便而有效的工具。     

Adsorbed hollow fiber‐based biological fingerprinting for the discovery of platelet aggregation inhibitors from Danshen–Honghua decoction

For lead compound discovery from natural products, hollow fiber cell fishing with chromatographic analysis is a newly developed method. In this study, an adsorbed hollow fiber‐based biological fingerprinting method was firstly developed to discover potential platelet aggregation inhibitors from Danshen–Honghua decoction. Platelets were seeded on the fiber and their survival rate was tested. Results indicated that more than 92% platelets survived during the whole operation process. Ranitidine and tirofiban were used as positive and negative control respectively to verify the reliability of the presented approach. The main variables such as amount of extract and stirring time that affect the adsorbed hollow fiber‐based biological fingerprinting process were optimized, and the repeatability of this method was also investigated. Finally, 12 potential active compounds in Danshen–Honghua decoction were successfully detected using the established approach and structures for nine of them were tentatively identified by liquid chromatography with mass spectrometry analysis. In addition, the in vitro platelet aggregation inhibition test was carried out for five of the nine hit compounds, and three active components, namely, lithospermic acid, salvianolic acid A, and salvianolic acid B were confirmed. These results proved that the proposed method could be an effective approach for screening platelet inhibitors from plant extracts.     

P2Y12 Purinergic Receptor and Brain Tumors: Implications on Glioma Microenvironment

Gliomas are the most common malignant brain tumors in adults, characterized by a high proliferation and invasion. The tumor microenvironment is rich in growth-promoting signals and immunomodulatory pathways, which increase the tumor’s aggressiveness. In response to hypoxia and glioma therapy, the amounts of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) strongly increase in the extracellular space, and the purinergic signaling is triggered by nucleotides’ interaction in P2 receptors. Several cell types are present in the tumor microenvironment and can facilitate tumor growth. In fact, tumor cells can activate platelets by the ADP-P2Y₁₂ engagement, which plays an essential role in the cancer context, protecting tumors from the immune attack and providing molecules that contribute to the growth and maintenance of a rich environment to sustain the protumor cycle. Besides platelets, the P2Y₁₂ receptor is expressed by some tumors, such as renal carcinoma, colon carcinoma, and gliomas, being related to tumor progression. In this context, this review aims to depict the glioma microenvironment, focusing on the relationship between platelets and tumor malignancy.     

Recent advances in platelet engineering for anti-cancer therapies

Platelets contribute a major role in hemostasis by clumping and coagulation at the site of blood vessel injuries. In light of recent findings of a close relationship between platelets and immunological response, as well as interactions between platelets and cancer cells, novel engineering strategies have emerged for the integration of platelets or platelet membrane (PM) with anti-cancer therapeutics. In this review, we discuss several recent innovations that use platelets or their membranes to circumvent host immune responses and target tumor cells with high specificity to deliver a range of pharmacological, photothermal, or immunologic agents for eradication of recalcitrant tumor cells. More specifically, we compare the relative advantages of using whole platelets versus single or hybrid PM to coat nanoparticle cargoes. These cargoes range from well-established anti-tumor apoptosis-inducing agents, to relatively new photothermal agents that can induce a feedback cascade in which they induce vascular damage to the tumor which recruits more platelet- or membrane-encapsulated agents to induce further damage. We also discuss the use of engineered platelets to produce programmed cell death-inducing platelet derived microparticles. This review provides an overview and future directions for this promising platelet-based biomimetic approach to anti-cancer therapy.     

A Novel Approach for the Surface Modification of Polymeric Membrane with Phospholipid Polymer

A new economic and convenient method to modify the surface of microporous polypropylene (PP) membranes with phospholipid polymer was given. The process included the photo-irradiated graft polymerization of N,N-dimethylaminoethyl methacrylate (DMAEMA) and the ring-opening reaction of the grafted polyDMAEMA with 2-alkyloxy-2-oxide-1,3,2-dioxo-phospholanes (AOP). Four AOPs, whose alkyloxy groups consisted of dodecyl, tetradecyl,hexadecyl and octadecyl moieties, were used to convert the grafted polyDMAEMA to phospholipidpolymers. FT-IR spectra confirmed the chemical change of membrane surface. Platelets adhesion experiment indicated that PP membrane with excellent blood compatible surface could be fabricated by this method.     

Growth of bismuth tri‐iodide platelets by the physical vapor deposition method

The work reports the growth of single BI₃ crystals with platelets habit. Platelets were grown by physical vapor deposition (PVD) in a high vacuum atmosphere and with argon, polymer or iodine as additives. Crystals grew in the zone of maximum temperature gradient, perpendicular to the ampoule wall. Crystals grown with argon as additive show a very shining surface, have hexagonal (0 0 l) faces, sizes up to 20 x 10 mm² and thicknesses up to 100 μm. They were characterized by optical microscopy and scanning electron microscopy (SEM). Dendritic‐like structures were found to be their main surface defect. SEM indicates that they grow from the staking of hexagonal unities. Electrical properties of the crystals grown under different growth conditions were determined. Resistivities up to 2 x 10¹² Ωcm (the best reported value for monocrystals of this material) were obtained. X‐ray response was measured by irradiation of the platelets with a ²⁴¹Am source of 3.5 mR/h. A comparison of results according to the growth conditions was made. Properties of the crystals grown by this method are compared with the ones measured for others previously grown from the melt. Also, results for bismuth tri‐iodide platelets are compared with the ones obtained for mercuric and lead iodide platelets. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Application of graphene nanoplatelets silica composite,prepared by sol–gel technology,as a novel sorbent in two microextraction techniques

In this study, the application of a novel nanomaterial composite was investigated in two microextraction techniques of solid‐phase microextraction and a needle trap device in a variety of sampling conditions. The optimum sampling temperature and relative humidity were 10°C and 20%, respectively, for both techniques with two sorbents of graphene/silica composite and polydimethyl siloxane. The two microextraction techniques with the proposed sorbent showed recoveries of 95.2 and 94.6% after 7 days. For the needle trap device the optimums desorption time and temperature were 3 min at 290°C and for SPME these measures were 1 and 1.5 min at 240–250°C for the graphene/silica composite and polydimethyl siloxane, respectively. The relative standard division obtained in inter‐ and intra‐day comparative studies were 3.3–14.3 and 5.1–25.4, respectively. For four sample the limit of detection was 0.021–0.25 ng/mL, and the limit of quantitation was 0.08–0.75 ng/mL. The results show that the graphene/silica composite is an appropriate extraction media for both techniques. Combining an appropriate sorbent with microextraction techniques, and using these in conjunction with a sensitive analytical instrument can introduce a strong method for sampling and analysis of occupational and environmental pollutants in air.