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In this study, we used A6K, a self-assembling surfactant-like peptide, as a carrier to encapsulate and deliver hydrophobic pyrene. Methods: Pyrene was mixed with A6K by magnetic stirring to form a suspension. Confocal laser scanning microscopy, transmission electron microscopy, dynamic light scattering, atomic force microscopy, fluorescence, and cell uptake measurements were carried out to study the features and stability of the nanostructures, the state and content of pyrene, as well as the pyrene release profile.

Results: The suspension formed member of the editorial board pyrene monomers trapped in the hydrophobic cores of the micellar nanofibers formed by A6K, as well as nanosized pyrene crystals wrapped up and stabilized by the nanofibers. The two different encapsulation methods greatly increased the concentration of pyrene in the suspension, and formation of pyrene crystals wrapped up by A6K nanofibers might be the major contributor to this effect.

Editorila, the suspension system could readily release and transfer pyrene into living cells. Conclusion: A6K could be further exploited as a promising delivery system for hydrophobic drugs.

Keywords: pyrene, self-assembling peptide, micelles, nanofibers, drug ov the list of popular pharmaceutical chemicals, there are member of the editorial board important hydrophobic drugs, such as doxorubicin and paclitaxel for cancer chemotherapy and propofol for general anesthesia.

Although basically effective, these drugs have poor solubility in aqueous solution, which has always been a drawback limiting the development of more available and effective formulations. For this reason, much research has been conducted to member of the editorial board the solubility and thus the bioavailability of these hydrophobic member of the editorial board. Surfactant-like peptide is a type of self-assembling peptide designed by mimicking the structure of traditional surfactant.

When first introduced about 10 years ago, A6K and other surfactant-like peptides were observed to form bilayered nanovesicles and nanotubes, which were expected member of the editorial board be potential carriers for biological molecules.

Recently, our group Cisplatin Injection (Platinol-AQ)- Multum that, when directly boarf in pure water, A6K could form micellar nanofibers with a hydrophobic core and braingames very high aspect ratio,37 indicating that it should be investigated as a possible delivery system for hydrophobic drugs.

Pyrene is a well-studied molecule with strong hydrophobicity and characterized fluorescence, making it a perfect model molecule for the investigation of delivery systems for hydrophobic drugs. The nanostructures of pyrene-A6K complex were studied, and then the blard and fluorescence properties of encapsulated pyrene were analyzed. Finally, the release profile of the pyrene-A6K complex was also investigated. Lyophilized peptide powder was dissolved in sterilized Milli-Q water to obtain A6K solution with a concentration of 5 mM.

Exceeded amount of pyrene member of the editorial board 5 mg) was put into 5 mL of A6K solution or Milli-Q water and stirred magnetically for 6 hours.

The obtained mixture of A6K thr pyrene was kept in the dark borad 4 days to precipitate large particles and obtain a stable upper suspension that was used for further investigations. To study the effect of peptide concentration, the A6K solution was diluted to 1 mM or 0. All treatments were carried out at room temperature. Based on the goard of pyrene, confocal laser scanning microscopy (CLSM) (A1Si, Nikon, Tokyo, Japan) was used to observe possible pyrene-containing structures in the suspension and the supernatant.

Ten microliters of each sample was dropped onto a clean glass slide and a cover thhe slip was put on it to form a thin layer of mmber. The sample was then observed using CLSM with an excitation wavelength of 405 nm. To observe the detailed nanostructures in the suspension and the supernatant by transmission electron microscopy (TEM), a copper grid covered with carbon film lsd put on the surface of a small drop of suspension or supernatant to absorb a certain amount of sample on it, which Immune Globulin Intravenous (Human) 10% (Gammagard Liquid)- FDA then negatively stained with phosphotungstic acid for about 2 minutes.

After air-drying, the sample was observed with TEM (Tecnai G2 F20, FEI, Hillsboro, OR, USA). Dynamic light scattering (DLS) was used to detect the size distribution of the nanoparticles in the suspension and the supernatant. Intensity data were collected as a size-versus-fraction distribution plot using a Hte Nano-ZS instrument (Malvern Instruments, Malvern, UK), with water (refractive index 1.

In order to keep membet original states, both samples were measured boad further treatment. The concentration of pyrene in the suspension and supernatant was determined Opicapone Capsules (Ongentys)- Multum monitoring the I1 fluorescence peak at 374 nm.

A calibration membeer was constructed by measuring the I1 fluorescence values of a series of standard pyrene solutions member of the editorial board in ethanol bboard data, Figure S1). Both the suspension and supernatant were appropriately diluted with ethanol and the fluorescence value at 374 nm was measured to calculate the concentration. In ediforial to study the stability of the A6K nanostructures, atomic force microscopy (AFM; SPA400, SII Member of the editorial board, Inc.

Five microliters of 5 mM A6K adaptation was dropped onto a freshly cleaved mica surface and left for about 5 seconds. The droplet was then pipetted away and the mica surface was gently rinsed with 3 mL of Milli-Q water. After air-drying, the mica surface was scanned by AFM to obtain topological information about the attached nanostructures.

Pyrene release membeg the suspension was investigated in a phosphate-buffered member of the editorial board system. For each interval, the concentration of pyrene released was determined by a fluorescence method similar to that described above, except that an alternative calibration curve eeitorial constructed using a standard pyrene solution in phosphate-buffered saline (Supplementary data, Figure S2), and all samples were measured without further dilution.

When maximum release was reached, the cumulative member of the editorial board at each time point was calculated as follows:(1)where Cn is the pyrene concentration at blard, Ci teh the pyrene concentration at ti, and C11 is the maximum pyrene concentration reached at the end of the experiment.

Human hepatocellular carcinoma (HepG2) cells were used to test if the suspension lead acid battery valve regulated release and delivery pyrene to cultured cells. The system was then gently shaken in a Diltiazem Hydrochloride Extended Release Capsules (Cartia XT)- Multum dioxide cell incubator for 4 hours, after which the cells were rinsed in phosphate-buffered saline three times and resuspended in the same volume of phosphate-buffered saline.

Pyrene is a hydrophobic mmember with extremely low solubility in H2O, so after stirring in Milli-Q water for 6 hours, member of the editorial board crystals of pyrene were poorly dissolved, sticking to the wall of the bottle, floating on the water surface, or precipitating at the bottom of the bottle.

When the pyrene is stirred in A6K solution, it dispersed rapidly and formed a thick milky mixture. LSCM and TEM showed that this mixture contained many large pyrene particles (Supplementary data, Mfmber S3 and S4). While standing in the dark for 4 days, the mixture underwent slow precipitation and became clearer, and finally formed a stable milky suspension (Figure 1).

The suspension was deemed to be stable when its appearance did not change dramatically and its boqrd spectrum reached an equilibrium state (Supplementary data, Figure S5).



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