Hydroxypropyl cellulose enhanced ionic conductive double-network hydrogels.

Ionic conductive hydrogels with both high-performance in conductivity and mechanical properties have received increasing attention due to their unique potential in artificial soft electronics. Here, a dual physically cross-linked double network (DN) hydrogel with high ionic conductivity and tensile strength was fabricated by a facile approach. Hydroxypropyl cellulose (HPC) biopolymer fibers were embedded in a poly (vinyl alcohol)­sodium alginate (PVA/SA) hydrogel, and then the prestretched PVA-HPC/SA composite hydrogel was immersed in a CaCl2 solution to prepare PVA-HPCT/SA-Ca DN hydrogels. The obtained composite hydrogel has an excellent tensile strength up to 1.4 MPa. Importantly, the synergistic effect of hydroxypropyl cellulose (HPC) and prestretching reduces the migration resistance of ions in the hydrogel, and the conductivity reaches 3.49 S/ m. In addition, these composite hydrogels are noncytotoxic, and they have a low friction coefficient and an excellent wear resistance. Therefore, PVA-HPCT/SA-Ca DN hydrogels have potential applications in nerve replacement materials and biosensors.

Nano-hydroxyapatite enhanced double network hydrogels with excellent mechanical properties for potential application in cartilage repair.

Hydrogels with desirable characteristics have been supposed to be potential materials for cartilage repair. However, the biomechanical, biotribological and biocompatible properties of hydrogels remain some crucial challenges. To address these challenges, we developed a dual physically cross-linked poly (vinyl alcohol)-(nano hydroxyapatite)/(2-hydroxypropyltrimethyl ammonium chloride chitosan) (PVA-HA/HACC-Cit) hydrogels with double-network (DN) through a simply freezing/thawing technique and an immersing process. The DN hydrogel with an optimized HA concentration exhibited outstanding fracture tensile stress (2.70 ± 0.24 MPa), toughness (14.09 ± 2.06 MJ/m3) and compressive modulus (0.88 ± 0.09 MPa). In addition, the PVA-HA/HACC-Cit DN hydrogels demonstrated remarkable anti-fatigue property, extraordinary self-recovery and energy dissipation ability due to their unique dual physically cross-linked structures. Moreover, the low friction coefficient, the predominant wear resistance property, as well as the excellent cytocompatibility were realized for the DN hydrogels because of the existence of nano-hydroxyapatite. Thus, this work puts forward a new strategy in the preparation of DN hydrogels for promising applications in cartilage repair.