Viscoelastic properties of a novel hydrogel/foam composites for nucleus pulposus replacement

Abstract

Neck and back pathologies cause considerable pain and suffering, and treatment costs tens of billions per year. A common source of problems is degeneration and herniation of the gel-like nucleus pulposus (NP) component of the intervertebral disc, and NP repair/replacement has been a long-term health care goal. We have investigated a novel class of hydrogel/foam composites to identify biocompatible materials with similar viscoelastic characteristics to the native tissue. Low acyl gellan gum (G) and agarose (A) in varying weight percentages were infused into Sugi® cellulose sponge material (F) to produce three candidate materials in addition to those samples without foam. Dynamic oscillatory shear tests and dynamic oscillatory axial compression test tests were conducted on the materials at frequencies between (f = 0.1–10 Hz) to measure elastic (storage) and viscous (loss) moduli in shear and compression conditions. The results show that hydrogel/foam composites show greater viscoelastic properties than hydrogel alone. Various materials of hydrogel and hydrogel/foam composite closely match the viscoelastic properties of native NP tissue.