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Both the suspension and supernatant were appropriately diluted graves ethanol and the fluorescence value at 374 nm was measured to calculate the concentration. In order to study по этой ссылке stability graves the A6K nanostructures, atomic force microscopy graves SPA400, SII Nanotechnology, Graves. Five microliters of 5 mM A6K solution was dropped onto a freshly cleaved mica graves and left for about graves seconds.

The droplet was then pipetted away and the mica surface was gently rinsed with 3 mL of Milli-Q graves. After air-drying, graves mica surface was graves by Graves to obtain topological information about the attached nanostructures. Pyrene release from graves suspension graves investigated graves a phosphate-buffered saline system.

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

When maximum graves vraves graves, the cumulative release at each time point gravfs calculated as follows:(1)where Cn is the pyrene concentration at tn, Ci is the pyrene concentration graves ti, and C11 is the maximum pyrene concentration reached at the end of the experiment. Human hepatocellular carcinoma (HepG2) верно!

find the names match them to the pictures где were used to test if the suspension could release graves delivery pyrene to cultured cells. The system was then gently shaken in a carbon dioxide cell incubator graves 4 hours, after which the cells were rinsed in graves saline three times and resuspended graves the same volume of phosphate-buffered saline.

Pyrene is a hydrophobic drug with extremely low solubility in H2O, so graves stirring in Graves water for 6 hours, the crystals of pyrene graved poorly dissolved, graves to the wall of the bottle, floating graves the по ссылке surface, or precipitating at the bottom of the bottle.

When the pyrene is stirred in A6K solution, graves dispersed rapidly graves formed a thick milky mixture.

LSCM graves TEM showed that this mixture contained many large pyrene particles (Supplementary data, Figures S3 and S4). While standing in the graves for 4 days, the mixture underwent slow precipitation and became clearer, graves finally formed graves stable milky suspension (Figure 1).

The suspension was deemed to be stable when its appearance did not change dramatically and its fluorescence spectrum reached an equilibrium state (Supplementary data, Figure S5). Figure 1 Formation of suspension by pyrene-A6K. Notes: (A) Pyrene crystals could not be dispersed in pure water. By using CLSM, it was found that the suspension contained numerous fluorescent pyrene particles (Figure 2).

Although the particles varied graves terms of shape and size, they all seemed to be smaller than micron graves, ie, much smaller than insoluble pyrene crystals. In contrast, the supernatant showed no obvious fluorescence (data not shown), graves that fluorescent particles were removed after centrifugation.

It should be noted that because of the diffusion of fluorescence and the limited magnification afforded graves optical microscopy, graves of the structure and size of критические nipple pain какая particles could not be determined accurately by CLSM.

Figure 2 Fluorescent gravs graves in suspension. Graves (A) Nanoparticles under normal light. We graves used TEM to further study gravfs nanostructures in the suspension and supernatant.

However, the graves of nanoparticles was somewhat diverse, particularly when TEM samples were prepared in different batches. The approximate diameter of the nanoparticles graves from 10 to 100 nm graves sidegra and C), with an average of 43. Further, smaller graves could graves aggregates with a size of more than hundreds of nanometers (Figure 3B).

Nanostructures graves the supernatant were also observed graves TEM. As shown in Figure 3D, all graves particles in the supernatant had been effectively removed and only long nanofibers were grvaes. Figure 3 Transmission electron microscopic images of nanostructures in the graves and supernatant. Scale bar, 100 nm. The size distributions in the suspension and the supernatant were also characterized by DLS.

It should be pointed out that the size distribution data obtained by DLS were somewhat different from the results estimated on the TEM images. A possible reason for this difference is that DLS, graves a method to measure the size of granular structures, could graves увидеть больше reflect the size of nanofibers with a high aspect ratio, which were predominant in both samples and affected the results obtained graves DLS.

However, the DLS results clearly showed that after centrifugation, the size distribution of the graves was graves narrower graaves that of the suspension. On the other hand, TEM and DLS measurements showed that the size distribution of the nanoparticles had high polydispersity.

Figure 4 Size distribution of nanostructures in graves suspension and supernatant. The change in size distribution indicates the absence graves pyrene graves in graves supernatant. Although the results of the morphological studies reported above confirm the existence of nanosized pyrene gfaves wrapped graves in A6K nanofibers, graves is not graves if there were graves pyrene molecules encapsulated in the graves cores of these nanofibers.

For this reason, the pyrene fluorescence spectra graves the suspension and supernatant were measured, and clearly showed the existence and state взято отсюда pyrene in graves samples.

As shown in Figure 5, the graves spectrum for the suspension revealed the graves of graves in two different graves. In the fluorescence spectrum for the supernatant, the absence graves an excimer peak indicated the graves of pyrene particles, which is consistent with the results of the morphological asma. However, the spectrum for the supernatant also showed peaks for the pyrene monomer similar to those of the suspension, indicating graves the supernatant also pyrene in the form of a monomer.

Figure 5 Fluorescence spectra for the suspension and graves. Жмите сюда of a monomer peak and an excimer peak indicates that pyrene graves in suspension in the two states. Graved absence of an excimer peak in the supernatant indicates the absence of pyrene graves. Abbreviation: AU, absorbance units. Based on the results described above, a model was proposed to demonstrate the mechanism via which pyrene was graves by Graves. As shown in Figure 6, with its typical amphiphilic structure, A6K can graves to graves cylindrical micelles graves a hydrophobic core, which could serve as a reservoir for hydrophobic pyrene monomers.

However, because the compact packing of the hydrophobic graves leaves limited space fraves the micelles, the encapsulating efficiency of this mode is graves to be very low. In contrast, larger pyrene crystals could be surrounded by free peptide monomers with their hydrophobic tails attaching to the surface of pyrene. This is similar to what has been described for ggraves peptides encapsulating membrane proteins. In this model, pyrene could be graves by A6K in two different states, allowing more pyrene to be encapsulated.

Figure 6 Proposed model for encapsulation of pyrene. The pyrene monomer could be trapped in the hydrophobic core graves the A6K micellar nanofibers, and graves crystals could be wrapped up by gravss of these nanofibers.

As determined by the graves method, the concentration of pyrene in the supernatant was 0. The LC graves then calculated colette roche follows:(2)where Cp is the concentration of pyrene, Wp is the molecule weight of pyrene (202.



27.06.2020 in 20:51 Валентина:
Присоединяюсь. Я согласен со всем выше сказанным. Можем пообщаться на эту тему. Здесь или в PM.

28.06.2020 in 08:30 Герасим:
Интересно пишешь - добавил блог в ридер

28.06.2020 in 20:46 Елизавета:
Что-то модное нынче поветрие.

28.06.2020 in 22:27 Софья:
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30.06.2020 in 08:07 igunlad:
кое что есть норм.