3 research outputs found
Simultaneous Enhancement of Cell Proliferation and Thermally Induced Harvest Efficiency Based on Temperature-Responsive Cationic Copolymer-Grafted Microcarriers
The development of large-scale suspension cell cultures
using microcarriers
has long been a focus of attention in the fields of pharmacy and biotechnology.
Previously, we developed cell-detachable microcarriers based on temperature-responsive
polyÂ(<i>N</i>-isopropylacrylamide) (PIPAAm)-grafted beads,
on which adhering cells can be noninvasively harvested by only reducing
the temperature without the need for proteolytic enzyme treatment.
In this study, to improve the cell harvest efficiency from bead surfaces
while maintaining cell adhesion and proliferation properties, we prepared
temperature-responsive cationic copolymer-grafted beads bearing a
copolymer brush consisting of IPAAm, positively charged quaternary
amine monomer (3-acrylamidopropyl trimethylammonium chloride; APTAC),
and hydrophobic monomer (<i>N</i>-<i>tert</i>-butylacrylamide;
tBAAm). The incorporation of positively charged APTAC into the grafted
copolymer brush facilitated bead dispersibility in a cell culture
system containing Chinese hamster ovary (CHO-K1) cells and consequently
allowed for enhanced cell proliferation in the system compared to
that of unmodified CMPS and conventional PIPAAm homopolymer-grafted
beads. Additionally, PÂ(IPAAm-<i>co</i>-APTAC-<i>co</i>-tBAAm) terpolymer-grafted beads exhibited the most rapid and efficient
cell detachment behavior after the temperature was reduced to 20 °C,
presumably because the highly hydrated APTAC promoted the overall
hydration of the PÂ(IPAAm-<i>co</i>-APTAC-<i>co</i>-tBAAm) chains. Therefore, PÂ(IPAAm-<i>co</i>-APTAC-<i>co</i>-tBAAm) terpolymer-grafted microcarriers are effective
in facilitating both cell proliferation and thermally induced cell
detachment in a suspension culture system
Mechanochromic Dynamic Covalent Elastomers: Quantitative Stress Evaluation and Autonomous Recovery
Stress evaluation in polymeric materials
is important in order
to not only spot danger in them before serious failure, but also precisely
interpret the destructive mechanism, which can improve the lifetime
and durability of polymeric materials. Here, we are able to visualize
stress by color changes, as well as quantitatively estimate the stress
in situ, in segmented polyurethane elastomers with diarylbibenzofuranone-based
dynamic covalent mechanophores. We prepared films of the segmented
polyurethanes, in which the mechanophores were incorporated in the
soft segments, and efficiently activated them by mechanical force.
Cleavage of the mechanophores during uniaxial elongation and their
recovery after the removal of the stress were quantitatively evaluated
by in situ electron paramagnetic resonance measurements, accompanied
by drastic color changes
Mechanochromic Dynamic Covalent Elastomers: Quantitative Stress Evaluation and Autonomous Recovery
Stress evaluation in polymeric materials
is important in order
to not only spot danger in them before serious failure, but also precisely
interpret the destructive mechanism, which can improve the lifetime
and durability of polymeric materials. Here, we are able to visualize
stress by color changes, as well as quantitatively estimate the stress
in situ, in segmented polyurethane elastomers with diarylbibenzofuranone-based
dynamic covalent mechanophores. We prepared films of the segmented
polyurethanes, in which the mechanophores were incorporated in the
soft segments, and efficiently activated them by mechanical force.
Cleavage of the mechanophores during uniaxial elongation and their
recovery after the removal of the stress were quantitatively evaluated
by in situ electron paramagnetic resonance measurements, accompanied
by drastic color changes