Flow induced stability of pluronic hydrogels: Injectable and unencapsulated nucleus pulposus replacement

摘要

Poloxamers, or pluronics, have been proposed as biomimetic substitutes for physiological gels. Concern regarding their ability to resist swelling under fluid flows has impeded their implementation. Using a combination of techniques including cryo-TEM and rapid X-ray imaging, we found that rapid flow rates stabilized the gels against dissolution. Energy balance calculations confirmed that disentanglement of individual micelles was not possible at time scales faster than the reptation time when the system response was that of a solid which dissipated the hydrodynamic force field via cooperative deformation. In-vivo tests were performed where the hydrogel was injected as a substitute for the nucleus pulposus following discectomy in dogs. The results indicated that the gel was still present after 3 months, and radiographs indicated that compression of the disc space was prevented despite the gel being exposed to constant perfusion.