Development of a biomimetic hydrogel cervical spinal cord surrogate for transverse compression across loading rates
Related Experiment Video
Updated: Nov 6, 2026
Development of Combinatorial Therapeutics for Spinal Cord Injury using Stem Cell Delivery
Published on: June 7, 2024
Paria Arjmandisarvestani1,2, Nicholas Cunha3, Parham Foroutan3
1Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK.
Study Design:
Experimental laboratory study; fully factorial hydrogel formulation design with mechanical benchmarking against published spinal cord tissue data.
Objectives:
To develop and characterise polyacrylamide-alginate (PAAm-alginate) double-network hydrogels as surrogates for the transverse compressive response of cervical spinal cord tissue, and to identify the formulation variables governing surrogate stiffness.
Setting:
University biomechanics laboratory, Adelaide, Australia.
Methods:
Twenty-seven formulations combined three alginate concentrations (4.7, 7.8, 10.3% w/v), three ionic crosslinkers (CaCl₂, FeCl₃, AlCl₃) and three immersion durations (1, 2, 3 h). 313 elliptical specimens were tested in transverse compression at four displacement rates (~0.01-140 s⁻¹). Characteristic curves were generated by arc-length re-parameterisation, compared by statistical parametric mapping, and benchmarked against published human and porcine cervical cord data.
Results:
All formulations showed J-shaped, rate-dependent viscoelastic responses. Loading rate produced the most consistently resolvable differences, followed by crosslinking ion, alginate concentration and immersion duration. Among formulation variables, crosslinking ion had the largest effect, alginate concentration showed diminishing gains above 7.8%, and immersion duration a modest, crosslinker-dependent effect. CaCl₂ formulations matched the benchmarks most closely at every rate; at ~50 s⁻¹, CaCl₂ / 10.3% / pooled 2 h + 3 h matched porcine cord in tangent modulus (~1180 kPa) and stress at benchmark failure strain (~490 kPa).
Conclusions:
PAAm-alginate double-network hydrogels reproduce the nonlinear, rate-dependent transverse compressive behaviour of cervical spinal cord tissue and can be tuned to published benchmarks, most closely under dynamic loading. They provide a basis for instrumentable cord surrogates for ex vivo injury biomechanics and surgical simulation.
Sponsorship:
University of Adelaide Medical School Development Grant.
