On the design and efficacy assessment of self-assembling peptide-based hydrogel-glycosaminoglycan mixtures for potential repair of early stage cartilage degeneration.

Peptide-based hydrogels are of interest for their potential use in regenerative medicine. Combining these hydrogels with materials that may enhance their physical and biological properties, such as glycosaminoglycans, has the potential to extend their range of biomedical applications, for example in the repair of early cartilage degeneration. The aim of this study was to combine three self-assembling peptides (P11 -4, P11 -8, and P11 -12) with chondroitin sulphate at two molar ratios of 1:16 and 1:64 in 130 and 230 mM Na+ salt concentrations. The study investigates the effects of mixing self-assembling peptide and glycosaminoglycan on the physical and mechanical properties at 37°C. Peptide alone, chondroitin sulphate alone, and peptide in combination with chondroitin sulphate were analysed using Fourier transform infrared spectroscopy to determine the β-sheet percentage, transmission electron microscopy to determine the fibril morphology, and rheology to determine the elastic and viscous modulus of the materials. All of the variables (peptide, salt concentration, and chondroitin sulphate molar ratio) had an effect on the mechanical properties, β-sheet formation, and fibril morphology of the hydrogels. P11 -4 and P11 -8-chondroitin sulphate mixtures, at both molar ratios, were shown to have a high β-sheet percentage, dense entangled fibrillar networks, as well as high mechanical stiffness in both (130 and 230 mM) Na+ salt solutions when compared with the P11 -12/chondroitin sulphate mixtures. These peptide/chondroitin sulphate hydrogels show promise for biomedical applications in glycosaminoglycan depleted tissues.