Preparation and properties of lignin-based dual network hydrogel and its application in sensing.

Ionic conductive hydrogels prepared from various biological macromolecules are ideal materials for the manufacture of human motion sensors from the perspective of resource regeneration and environmental sustainability. However, it is now difficult to develop conductive hydrogels including excellent self-healing and mechanical properties, mainly due to their inherent trade-off between dynamic cross-linked healing and stable cross-linked mechanical strength. In this work, alkali lignin-Polyvinyl alcohol-polyacrylic acid double network conductive hydrogels with high mechanical strength and good self-healing properties were prepared. We formed the primary network structure by hydrogen bonding interaction between polyvinyl alcohol, alkali lignin and polyacrylic acid, and the secondary network structure by coordination interaction with polyacrylic acid through the addition of Fe3+. The added lignin acts as a dynamic linkage bridge in a porous network mediated by multiple ligand bonds, imparting superior mechanical properties to the hydrogels. The relationships between the alkali lignin and iron ion dosage and the comprehensive properties of hydrogels (adhesion, antibacterial, self-healing, electrical conductivity and mechanical properties) were studied in detail. On this basis, the hydrogels explored the role of lignin in the regulation of hydrogels properties and revealed the self-healing and conductive mechanism.

Establishment of a rabbit model of lumbar laminectomy and bone grains replantation / 中国比较医学杂志

Objective To establish a rabbit model of lumbar laminectomy and bone grains replantation and provide experimental evidence for the clinical application.Methods Eighteen healthy male New Zealand rabbits were selected and randomly divided into two groups:the control group (n=6) and experimental group (n=12).The rabbits of control group were given general anesthesia, and taking the L5 spinous process as the center to perfom left L5 laminectomy, using a micro lancet forceps to slowly bite the lamina and ligamentum flavum for fenestration and exposed to an approximately 0.8 cm x 0.3 cm sized bone window and then sutured the skin.The rabbits of experimental group were exposed to an approximately 0.8 x 0.3 cm sized bone window as well, and bone fragments were cut into small grains.Then the small bone grains were embedded in medical collagen sponge, to form an arch shape, and replanted them to the site of epidural fenestration.CT scan and histological changes were observed at 4, 8 and 12 weeks after operation.Results At 8 weeks after operation, CT examination showed that in the experimental group, a thin bone plate was formed by the bone grains.At 12 weeks after operation, the bone plate became thicker and was connected with the vertebral bone, and with continuous bone trabeculae.The spinal canal and volume were not obviously changed, and no spinal cord compression was observed. The rabbits of control group showed segment lamina defects, a small scar protruding into the spinal canal, and the vertebral canal was not completely reconstructed. Conclusions The bone grains replantation can effectively promote bone reconstruction in the laminectomized rabbits, and the formed bone plate can prevent epidural scar from intruding into the spinal canal, and can reduce the postlaminectomy adhesion.