53
54
4.7.2. Fibrin Glue with 0.3125% Sodium carboxymethyl cellulose
In Figure 4.14, two magnification levels, one at 500x and another at 1000x, of fibrin glue with 0.3125% sodium carboxymethyl cellulose are shown along with EDS data. A dense non-porous structure can be observed. Some crystalline structures can be observed. EDS analysis reveals that these structures are mostly carbon-based.
Figure 4.14: SEM and EDS of fibrin glue with 0.3125% CMC
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4.7.3. Fibrin Glue with 0.6250% Sodium carboxymethyl cellulose
In Figure 4.15, two magnification levels, one at 500x and another at 1000x, of fibrin glue with 0.6250% sodium carboxymethyl cellulose are shown along with EDS data. A dense non-porous structure can be observed. Moreover, the fibrin clot structure with densely cross-linked networks can be seen in the images. This could be one of the reasons for the high adhesion strength of fibrin glue with this concentration of polymer. EDS analysis reveals that the white particle-like structures are mostly carbon-based.
Figure 4.15: SEM and EDS of fibrin glue with 0.6250% CMC
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4.7.4. Fibrin Glue with 1.25% Sodium carboxymethyl cellulose
In Figure 4.16, two magnification levels, one at 1000x and another at 3000x, of fibrin glue with 1.25% sodium carboxymethyl cellulose are shown along with EDS data. A dense non-porous structure can be observed with lots of crystals. However, the dense cross-linking that was observed with 0.6250% of the polymer was not present here. At lower concentrations, CMC improved the cross-linking capability without hampering the chelating effect of calcium.
However, at higher concentration, the chelating effect of calcium was lowered due to more reactive sodium ion thus reducing the adhesion strength and can be observed as well from the absence of dense cross-linked structure and presence of excess sodium crystals (Godal 1969;
Wang, Pins, and Silver 1995). This could suggest a slightly lower adhesion strength at this concentration. EDS analysis reveals that these structures contain mostly sodium, so these are produced from the polymer itself and are detectable due to the higher concentration.
Figure 4.16: SEM and EDS of fibrin glue with 1.25% CMC
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4.7.5. Fibrin Glue with 0.3125% Methylcellulose
In Figure 4.17, two magnification levels, one at 500x and another at 1000x, of fibrin glue with 0.3125% methylcellulose are shown along with EDS data. A dense non-porous structure can be observed. Some structures could not be observed due to surface charging problems after EDS analysis of the sample multiple times. EDS analysis reveals that the crystalline structures are mostly carbon-based.
Figure 4.17: SEM and EDS of fibrin glue with 0.3125% MC
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4.7.6. Fibrin Glue with 0.6250% Methylcellulose
In Figure 4.18, two magnification levels, one at 500x and another at 1000x, of fibrin glue with 0.6250% methylcellulose are shown along with EDS data. A dense non-porous structure with dense fibers and crystals can be observed. Some cross-linked structures are also visible. This could suggest the reason for high adhesion strength. EDS analysis reveals that the fibrous structures are mostly carbon-based.
Figure 4.18: SEM and EDS of fibrin glue with 0.6250% MC
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4.7.7. Fibrin Glue with 1.25% Methylcellulose
In Figure 4.19, two magnification levels, one at 500x and another at 1000x, of fibrin glue with 1.25% methylcellulose are shown along with EDS data. A dense non-porous structure can be observed. Though some cracks can be observed, these are formed due to the fragile nature of the lyophilized fibrin glue. Some dense and concentrated crystalline structures can be observed as well. EDS analysis reveals that these structures are mostly carbon-based and might be due to the higher concentration of methylcellulose.
Figure 4.19: SEM and EDS of fibrin glue with 1.25% MC
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4.7.8. Comparison of Fibrin Glue structure with different concentration of sodium carboxymethyl cellulose
In Figure 4.20, the SEM images of fibrin glue with different concentrations of sodium carboxymethyl cellulose at 1000x magnification are shown. Image A is for 0.3125%, B for 0.6250% and C is for 1.25% concentration of polymer. At increasing concentration, the presence of the crystalline bodies increases. Moreover, EDS analysis for image C reveals that these crystalline bodies do contain a higher concentration of sodium. Hence, a fairly good hypothesis is that the crystalline bodies observed in all three images originated from sodium carboxymethyl cellulose. Moreover, a dense cross-linking structure can only be observed at a concentration of 0.6250% as seen in image B. The adhesion strength data also suggest higher values at that concentration. One hypothesis is that a high concentration of sodium carboxymethyl cellulose has a detrimental effect on adhesion strength. Furthermore,
A B
C
Figure 4.20: SEM characterization of fibrin glue with different concentration of sodium carboxymethyl cellulose at 1000x magnification
61 cytotoxicity data also suggests lower cell survival at higher concentrations, providing a basis for this hypothesis.
4.7.9. Comparison of Fibrin Glue structure with different concentration of methylcellulose
In Figure 4.21, the SEM images of fibrin glue with different concentrations of methylcellulose at 1000x magnification are shown. Image A is for 0.3125%, B for 0.6250% and C is for 1.25%
concentration of polymer. For methylcellulose, the SEM images are quite distinct. For SEM image A, the fibrous crystalline structures cannot be observed easily. For images B and C, the crystalline structures have become denser. From adhesion strength data, it can be observed that 1.25% has the highest value, 0.3125% has the lowest value and 0.6250% lies in between. One
B A
C
Figure 4.21: SEM characterization of fibrin glue with different concentration of methylcellulose at 1000x magnification
62 hypothesis is that the denser crystalline structure might be responsible for the increasing adhesion strength.