Fig. 3: The self-healing, adhesion, lubricity properties of the injectable hydrogel.

A Photographs depicting the self-curing process of SO₃⁻/DA-HA hydrogel precursor initiated by DAGQD@Cu@KGN SAN. B The injectable property of DAGQD@Cu@KGN-SO₃⁻/DA-HA hydrogel. C Rheological properties of DAGQD@Cu@KGN-SO₃⁻/DA-HA hydrogel. D Images illustrating the self-curing process of DAGQD@Cu@KGN-SO₃⁻/DA-HA hydrogel in the cartilage defect of a rabbit knee joint. E Hydrogel self-healing ability. F Schematic depiction of the self-healing mechanism. G Coefficient (COF) comparison between Cu²⁺-SH-HA hydrogel, SAN-SH-HA hydrogel, and SAN-SO₃⁻-HA hydrogel (n = 3 samples). H COF variation of SAN-SO₃⁻/DA-HA hydrogel with different ratios of SO₃⁻-HA and DA-HA (n = 3 samples). I Adhesion strength of SAN-SO₃⁻/DA-HA hydrogel with different ratios of SO₃⁻-HA and DA-HA on cartilage samples (n = 3 samples). J Adhesion strength of the hydrogel with different concentrations of SAN on cartilage samples (n = 3 samples). K Anatomic picture of hydrogel adhesion in joint. L The FESEM and (M) metallographic microscopy image of hydrogel-cartilage cross-section (n = 3 independent experiments). N Illustration of the bioadhesion mechanism of DAGQD@Cu@KGN SAN hydrogel on cartilage tissue, involving (1) hydrogen bonds, (2) cation-π interaction, and (3) covalent linking. O Compressive strength and (P) compression modulus analysis of the hydrogel with varying concentrations of DAGQD@Cu@KGN SAN (n = 3 samples). (Data are presented as the mean ± SD. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post-hoc test, with a value of *P < 0.05, **P < 0.01, and ****P < 0.001).