Fig. 3. SEM photomicrographs of PLLA, PCLA, PCL scaffolds prepared with
the addition of a gelatin nano-non-woven.
On the bottom surface of the scaffold obtained from PLLA with the
addition of PVP and gelatin nano-non-wovens, rare small pores of a
diameter of 5–10 µm were observed. On the upper surface, numerous,
irregular pores of the size of 20–40 µm were also present. Between them
pores of 5–15 µm in size were present. In the cross-section of the
scaffold, large irregular, nearly oval pores 20–70 µm, and up to about
100 µm in size could be seen. Compared to the scaffold obtained by using
only a gelatin nano-non-woven, pores were more linked, and their walls
were thinner (1–2 µm). As in the previous case, significantly smaller
round pores (ca. 1 µm) could be seen in the walls of larger pores.
Rare pores were having 5–10 µm, sometimes 20 µm in diameter were
observed on the bottom surface of the scaffold prepared from PLLA with
the addition of PVP, Pluronic®, and a gelatin nano-non-woven (Fig. 7).
On the other hand, numerous irregular 20–40 µm pores could be seen on
the upper surface. Irregular, nearly oval pores of the size of 20–80 µm
are present in the cross-section of the scaffold. In contrast to the
previous results, walls of these pores 5–10 µm thick, not only
contained perforations but – first of all, their cross-section was
distinctly divided into segments. It means that the inner walls of these
pores did not have a solids structure.
Due to the promising results about the use of gelatin nano-non-woven in
preparing scaffolds from poly-L-lactide, it was decided to test the
effectiveness of the method for obtaining scaffolds from other
biodegradable polymers: block copolymer
poly(ε-caprolactone-b -lactide) and poly(ε-caprolactone).
Rare pores having less than 5 µm in diameter could be seen on the bottom
surface of the scaffold prepared from block copolymer
poly(ε-caprolactone-b -lactide) using gelatin nano-non-woven.
Irregular, 20–50 µm pores are visible on the upper surface. Nearly oval
pores of the size of 20–60 µm could be seen in the cross-section of the
scaffold. Between them, there are smaller (10–15 µm) pores. These pores
were also located in the inner 1–3 µm thick walls of larger pores.
Pores having 5–10 µm and 20 µm in diameter are present on the bottom
surface of the scaffold prepared from PCLA with the addition of PVP and
the gelatin nano-non-woven. Irregular 20–40 µm pores could be seen on
the upper surface. In the cross-section of the scaffold oval, 50–80 µm
pores are present in the cross-section of the scaffold. Additionally,
the walls of these pores (3–5 µm thick) contained perforations.
Small pores (approx. 5–15 µm) could be seen on the bottom surface of
the scaffold prepared from PCLA with the addition of PVP, Pluronic®, and
the gelatin nano-non-woven. Irregular (20–40 µm) pores could be seen on
the upper surface. Oval 40–80 µm pores could be seen in the
cross-section of the scaffold. In the inner walls of these pores,
smaller (1–2 µm) pores were present. Walls of these pores had 5–10 µm
in thickness and were not stable – they consisted of some segments.
Another material tested was poly(ε-caprolactone). Unfortunately,
scaffolds prepared from this polymer have shown severe contraction
during a rinsing bath. Scaffolds were twisted, and their structure has
wrinkles and discontinuities. The use of pressing roll to prevent
contractions of the material failed to provide the desired effect.
Although the scaffolds did not twist, numerous discontinuities of the
material were seen in their structure. This effect could be caused by
too low glass transition temperature of PCL, –60°C (for PLLA: +65°C),
probably inadequate for the conditions used in this method (–18 and
+40°C).
Small (less than 5 µm) and rarely distributed pores could be seen on the
bottom surface of the scaffold prepared from PCL with the use of a
gelatin nano-non-woven. On the upper surface, there were irregular
20–40 µm pores. Between them smaller (approx. 5 µm) pores were present.
Oblong pores were having 40–80 µm in length were present in the
cross-section. Walls of the pores were thick (5–15 µm) and twisted.
A number of pores of the size 5–10 µm could be seen on the bottom
surface of the scaffold prepared from PCL with the addition of PVP and a
gelatin nano-non-woven. Irregular pores of the size of 20–40 µm could
be noted on the upper surface. Oblong (40–80 µm) pores could be seen in
the cross-section of the scaffold. Walls of these pores were thick
(5–15 µm) and twisted.
Few pores of the size of 5–15 µm could be seen on the bottom surface of
the scaffold prepared from PCL with the addition of PVP, Pluronic®, and
a gelatin nano-non-woven. Irregular pores of the size of 20–40 µm could
be noted on the upper surface. Oblong pores of the size of 40–60 µm
were present in the cross-section of the scaffold. As in the previous
cases for this polymer, walls of pores were thick (5–15 µm) and
twisted. Besides, their structure was not solid but divided into
segments.
Table 2. Morphology of the membranes