Functional compressive mechanics and tissue biocompatibility of an injectable SF/PU hydrogel for nucleus pulposus replacement

Abstract

In spinal degenerative disease, an injectable liquid hydrogel can fill in defect entirely, lessen the danger of implant relocation and following loss of disc height, minimizing the operative trauma. Here, we propose an injectable in-situ chemically cross-linked hydrogel by a two-component reaction of liquid silk fibroin with liquid polyurethane at physiological temperature conditions. Confined compression tests and fatigue tests were reported to assess physical properties of the hydrogel. Impact of different diameter on the biomechanical behaviours was tested to evaluate the clinical potentiality of the hydrogel for replacing nucleus pulposus. Degradation behaviours in different solutions and animal experiments were also investigated to examine the tissue biocompatibility of the hydrogel. The hydrogel modulus was affected by the hydrogel geometrical (diameter) parameters. SF/PU composite hydrogel can survive a million cycles, unconstrained fatigue resistance. More importantly, in vivo biocompatibility using New Zealand white rabbits, showed good biocompatibility over a three-month period in culture. Particularly, they showed the significant clinical merit of providing stronger axial compressive stiffness on confined compression test. Based on the outcomes of the present research, the SF/PU composite hydrogel may provide significant advantages for use in future clinical application in replacing nucleus pulposus field.

Amorphous Silk Fibroin Nanofiber Hydrogels with Enhanced Mechanical Properties

“…The introduced ingredients and higher SF concentration usually influence the biocompatibility of the formed hydrogels, impairing their possible applications in tissue engineering. Novel methods without negative influence on biocompatibility are preferable option for SF hydrogels …”

Recent advances of hydrogel‐based biomaterials for intervertebral disc tissue treatment: A literature review

“…In the recent subsequent experiments, the fatigue test was carried out to further demonstrate the good mechanical properties and biocompatibility in vivo. After 1 million fatigue tests, there are still no obvious changes in the height and diameter of the hydrogel, which proves the durability of the material (J. Hu et al., 2017).…”

In situ Enabling Approaches for Tissue Regeneration: Current Challenges and New Developments

“…Moreover, injectable in situ crosslinking chitosan-hyaluronic acid based hydrogels have shown notable potential in abdominal tissue regeneration (Deng et al, 2017). Other advances have been made in spinal degenerative disease, for example an in situ injectable chemically crosslinked hydrogel formed by a two-component reaction of liquid silk fibroin with liquid polyurethane at physiological temperature conditions which was shown to fulfill an entire defect, reducing the danger of implant relocation and the subsequent loss of disk height, minimizing the operative trauma (Hu et al, 2017). Efforts were also made in cartilage regeneration using an injectable hydrogel with transforming growth factor (TGF)-β1, which was considered capable of promoting chondrogenesis (Zhou et al, 2017).…”