Intervertebral disc implant

R Kandel; JP Santerre; SQ Li
US Patent App. 10195044, 2019

The present inventors have generated the tissues that comprise the intervertebral disc and have established viable protocols and tissue conditions that facilitate integration of all the tissue components into one functional tissue so it can weight bear following implantation. In particular, the inventors have prepared an intervertebral disc implant containing different integrated components (the annulus fibrosus (AF) wherein the AF is comprised of multiple layers of tissue each layer having fibres that are oriented at oblique angles to fibres of the adjacent layer, the nucleus pulposus (NP) and, optionally, at least one cartilaginous layer or end plate.

Mechanical Testing of Multiphasic Constructs

On day 21 of culture, the bulk compressive modulus of the multiphasic construct's cartilaginous tissue was determined using stress relaxation testing on the Mach-1 mechanical testing platform (Biomomentum, Laval, QC, Canada) with a 0.65 mm-diameter indenter as previously described. Interfacial shear strength was measured as previously described (St-Pierre J-P, et al, Acta biomaterialia, 2012; 8: 1603-15). The peak shear force before failure was calculated from the maximum stress, and the energy absorbed by the interface before failure was calculated by integrating the stress-strain curve up to the strain at which the peak shear force occurred.