15 research outputs found
Tough and Porous Hydrogels Prepared by Simple Lyophilization of LC Gels
Porous hydrogels possessing mechanical
toughness were prepared
from sacran, a supergiant liquid crystalline (LC) polysaccharide produced
from Aphanothece sacrum. First, layered
hydrogels were prepared by thermal cross-linking of film cast over
a sacran LC solution. Then, anisotropic pores were constructed using
a freeze-drying technique on the water-swollen layered hydrogels.
Scanning electron microscopic observation revealed that pores were
observable only on the side faces of sponge materials parallel to
the layered structure but never on the top or bottom faces. The pore
size, porosity, and swelling behavior were controlled by the thermal-cross-linking
temperature. To clarify the freezing effect, a freeze–thawing
method was used for comparison. The freeze–thawed hydrogels
also formed layers but no pores. The mechanical properties and network
structures of hydrogels were also studied, clarifying that porous
hydrogels, even those with a high quantity of pores, were tough owing
to the pores orienting along the layer direction like tunnels
Surface-Selective Control of Cell Orientation on Cyanobacterial Liquid Crystalline Gels
Liquid crystalline hydrogels (LCGs)
with layer structures and oriented
pores were created using sacran which is a cyanobacterial heteropolysaccharide
possessing functional sulfate, carboxylate, and amide groups in common
with glycosaminoglycan. The LCG biocompatibility with L929 mouse fibroblasts
was confirmed under the appropriate conditions. Enhanced growth and
proliferation of L929 cells without exhibiting any toxicity were confirmed.
The water contact angle and protein adsorption ability on the LCG
were well-controlled by the cross-linking degree. Additionally, fibroblasts
were finely oriented on the LCG side face where layer edges made a
striped morphology on its surface, whereas the flat top faces of the
LCG did not induce any specific cell orientation
Surface-Selective Control of Cell Orientation on Cyanobacterial Liquid Crystalline Gels
Liquid crystalline hydrogels (LCGs)
with layer structures and oriented
pores were created using sacran which is a cyanobacterial heteropolysaccharide
possessing functional sulfate, carboxylate, and amide groups in common
with glycosaminoglycan. The LCG biocompatibility with L929 mouse fibroblasts
was confirmed under the appropriate conditions. Enhanced growth and
proliferation of L929 cells without exhibiting any toxicity were confirmed.
The water contact angle and protein adsorption ability on the LCG
were well-controlled by the cross-linking degree. Additionally, fibroblasts
were finely oriented on the LCG side face where layer edges made a
striped morphology on its surface, whereas the flat top faces of the
LCG did not induce any specific cell orientation
Orientation Analysis of Polymer Chains in Optically Transparent Biopolyimides Having Rigid and Bending Backbones
Mechanically stable egg white protein based immobilization carrier for β-D-galactosidase: Thermodynamics and application in whey lactose hydrolysis
Highly Stretchable, Elastic, and Ionic Conductive Hydrogel for Artificial Soft Electronics
High conductivity, large mechanical strength, and elongation are important parameters for soft electronic applications. However, it is difficult to find a material with balanced electronic and mechanical performance. Here, a simple method is developed to introduce ion-rich pores into strong hydrogel matrix and fabricate a novel ionic conductive hydrogel with a high level of electronic and mechanical properties. The proposed ionic conductive hydrogel is achieved by physically cross-linking the tough biocompatible polyvinyl alcohol (PVA) gel as the matrix and embedding hydroxypropyl cellulose (HPC) biopolymer fibers inside matrix followed by salt solution soaking. The wrinkle and dense structure induced by salting in PVA matrix provides large stress (1.3 MPa) and strain (975%). The well-distributed porous structure as well as ion migration–facilitated ion-rich environment generated by embedded HPC fibers dramatically enhances ionic conductivity (up to 3.4 S m −1 , at f = 1 MHz). The conductive hybrid hydrogel can work as an artificial nerve in a 3D printed robotic hand, allowing passing of stable and tunable electrical signals and full recovery under robotic hand finger movements. This natural rubber-like ionic conductive hydrogel has a promising application in artificial flexible electronics