Thermo/hydration responsive shape memory polymers with enhanced hydrophilicity for biomedical applications Page: 9
10 p.View a full description of this article.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Smart Mater. Struct. 32 (2023) 015006
1000
100 [-
10
0 10 20 30 40 50 60
Time (min.)1000
100
100.1
1
Time (min.)10
(b)
1000
--Omol%
DAc 10mol%
--DAc 20mol%
DAc 30mol%
-DAc 40mol%0 10 20 30 40 50 60
Time (min.)Figure 7. Softening profiles of (a) DAc-modified, (b) PAc-modified SMPs, and (c) logarithmic scale of time to show onset temperature with
varying monomer composition.The unmodified polymer started to soften at t = 3 min
and completely softened at t = 19 min to reach the equilib-
rium state. The onset time for softening decreased as the DAc
molar ratio increased, and E' also decreased after complete
softening. The 40 mol% DAc-modified polymer, which had
the highest DAc ratio, began to soften at t = 0.5 min and
fully softened in only 8 min. PAc induced a similar effect
on softening, but the strength of the effect was lower than
that of DAc. The 40 mol% PAc-modified polymer completely
softened in approximately 10 min. These experimental res-
ults were strongly correlated with the shape recovery beha-
vior under physiological conditions. Therefore, we can con-
clude that the improved hydrophilicity and reduced Tg under
wet conditions enabled faster softening, which resulted in sub-
stantially faster shape recovery.
3.6. Biocompatibility tests
The biocompatibility of the polymers is also crucial
because they were designed for implantable devices. It
was tested based on the MTT (3-(4,5-dimethylthiazol-2-
yl)-2,5-diphenyltetrazolium bromide) assay for the unmod-
ified, 40 mol% DAc-modified, and 40 mol% PAc-modifiedpolymers. In the MTT assay, succinate dehydrogenase in the
mitochondria of live cells converts yellow MTT to purple
MTT-formazan. The dehydrogenase is involved with the res-
piratory chain; therefore, the activity of the enzyme, which is
estimated from the optical density at 570 nm (OD570), can
be an indicator of cell viability. The cell viabilities estimated
from the MTT assay for each polymer were 88.4 7.4%,
91.5 10.8%, and 91.2 4.0% for the unmodified, 40 mol%
DAc-modified, and 40 mol% PAc-modified polymers, respect-
ively (figure S14). Based on ISO 10993-5 [46], when the
viability is lower than 70%, the material is considered cyto-
toxic. Therefore, it was confirmed that the 40 mol% DAc- and
40 mol% PAc-modified polymers and unmodified polymers
were biocompatible. If modification by DAc and PAc induced
cytotoxicity, adding 40 mol% should provide the worst result.
Hence, all the polymers in this work were biocompatible.
4. Conclusion
In this study, we designed new thiol-ene/acrylamide SMPs
using DAc as a hydrophilic monomer to control the ther-
momechanical properties and hydrophilicity of current thiol-
ene SMPs. Soaked DMA and observation of shape recovery(a)
- Omol% ---- PAc 30mol%
- - - - - PAc 10mol% PAc 40mol%
- PAc 20mol%(c)
-- Omol%
- DAc 10mol%
-- DAc 20mol%
- PAc 30mol%
- PAc 20mol%
-----PAc 30mol%
PAc 40mol%Y Suzuki et al
100
10
1-~ -0o1 -
D~c 0mo1 ",-
D~c 3mo1%...-
D~c 4mo1% . " -
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Suzuki, Yuta; Hu, Qichan; Batchelor, Benjamin; Voit, Walter & Ecker, Melanie. Thermo/hydration responsive shape memory polymers with enhanced hydrophilicity for biomedical applications, article, December 5, 2022; (https://digital.library.unt.edu/ark:/67531/metadc2179416/m1/9/: accessed July 18, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT College of Engineering.