Natural-Wood-Inspired Ultrastrong Anisotropic Hybrid Hydrogels Targeting Artificial Tendons or Ligaments

Abstract

Hydrogels are able to mimic the flexibility of biological tissues or skin, but they still cannot achieve satisfactory strength and toughness, greatly limiting their scope of application. Natural wood can offer inspiration for designing high-strength hydrogels attributed to its anisotropic structure. Herein, we propose an integrated strategy for efficient preparation of ultrastrong hydrogels using a salting-assisted prestretching treatment. The as-prepared poly­(vinyl alcohol)/cellulose nanofiber hybrid hydrogels show distinct wood-like anisotropy, including oriented molecular fiber bundles and extended grain size, which endows materials with extraordinarily comprehensive mechanical properties of ultimate breaking strength exceeding 40 MPa, strain approaching 250%, and toughness exceeding 60 MJ·m–3, and outstanding tear resistance. Impressively, the breaking strength and toughness of the reswollen preoriented hydrogels approach 10 MPa and 25 MJ·m–3, respectively. In vitro and in vivo tests demonstrate that the reswollen hydrogels do not affect the growth and viability of the cells, nor do they cause the inflammation or rejection of the mouse tissue, implying extremely low biotoxicity and perfect histocompatibility, showcasing bright prospects for application in artificial ligaments or tendons. The strategy provided in this study can be generalized to a variety of biocompatible polymers for the fabrication of high-performance hydrogels with anisotropic structures.

A Nanophase Separation Strategy toward Organohydrogel Fibrous Sensors with Ultralow Detection Limit and High Strain Sensitivity

“…Owing to the orientational freezing process, these nanofibers are nearly uniformly oriented, which is believed to enhance the mechanical performance of organohydrogels. 28 With an increasing amount of TANI in PTOHFs (from 0, 3, 5, to 7.5 wt % corresponding to POHF, PTOHF-1, PTOHF-2, and PTOHF-3, respectively), the pore sizes of the micropores decrease, and more amorphous bulk is observed in PTOHF-3. The presence of nanofibers in POHF samples suggests that the formation of these nanofibers is unrelated to the addition of TANI (Figure S2a).…”

Antifreezing, Antidrying, and Conductive Hydrogels for Electronic Skin Applications at Ultralow Temperatures

“…The MXene hydrogels after salting out exhibit progressive damage characterized by step fracture because an external force induces the aggregated molecular chains to orient. Besides, the tail peak of the stress–strain curve becomes longer owing to the formation of molecular fiber bundles. , Specifically, for the MXene hydrogel without the LiCl treatment, the tensile strength is 90 kPa and the elongation at the break reaches 200%. After being immersed in 10 wt % of LiCl solution, the PMS-1 hydrogel swells owing to the absorbed numerous water molecules, resulting in decreased mechanical properties caused by the reduced density of polymer networks.…”

Triple‐Mechanism Enhanced Flexible SiO2 Nanofiber Composite Hydrogel with High Stiffness and Toughness for Cartilaginous Ligaments

“…As shown in Figure 7b and Figure S7 ( Supporting Information), FDA‐SNF/PVA exhibits high cell viability (>94%) (See Experimental Section and Table S2, Supporting Information for calculation of cell viability) and only a few dead cells are detected on the surface after 72 h, similar to the control, which indicates that FDA‐SNF/PVA has no adverse effect on cell growth and is cytocompatible. [ 64,65 ]…”