Figure 4. CS-adhesive mechanical properties and in vivo durability.

Hydrogel was implanted in chondral defects of a rabbit with or without the CS adhesive (n = 7). a, MRI of the articular defects treated with the CS adhesive and hydrogel (+CS) demonstrated an MRI signal and T₂ signal change, whereas defects that were not treated with CS adhesive before hydrogel placement (−CS) were empty after 5 weeks (n = 3). b, The CS-adhesive interface did not fracture when tensile and shear forces were applied. However, the hydrogel bulk failed when the adhesive was present (+CS). Without the CS adhesive (-CS), the hydrogel and cartilage separated easily at the interface. To determine the adhesive strength of the CS adhesive, highly crosslinked HEMA was bound to the cartilage surface and exposed to shear and tensile forces. The strength of the interface is presented in Table 1. c–e, Safranin-O staining of defects in the rabbit treated with CS adhesive and hydrogel (c), hydrogel alone (d) and no treatment (e) revealed enhanced proteoglycan deposition and tissue development when adhesive and hydrogel were present.