Fig. 4: Preparation, characterization and in vitro mechanical properties of the Mg-ALN@Gel bone adhesive.

a Schematic representation of the preparation of the Mg-ALN@Gel bone adhesive. b Gelation time of Mg-ALN@Gel. c Stability of the Mg-ALN@Gel bone adhesive. d Injectability and shear thinning behavior of the adhesive. e Self-healing ability of the adhesive. f Distribution of Mg-ALN within the adhesive, with red fluorescence representing rhodamine-modified Mg-ALN. The release of Mg²⁺ (g) and ALN (h) from the Mg-ALN@Gel bone adhesive was measured at different time points after incubation at pH 4.5, 6.8, or 7.4 (n = 3 independent samples). i Photograph showing strong adherence of the Mg-ALN@Gel bone adhesive to a glove surface. j Photograph demonstrating the Mg-ALN@Gel bone adhesive effectively rejoining crushed porcine ribs. k Mechanism of adhesion between hydrogel and bone surface and cohesion of internal hydrogel. l Schematic representation of end-to-end adhesive strength test setup. m Representative force-displacement curve from end-to-end tensile testing. n The end-to-end maximum adhesive strength (n = 3 independent samples). o Schematic representation of lap-shear adhesive strength test setup. p Representative force-displacement curve from lap-shear tensile testing. q The lap-shear maximum adhesive strength (n = 3 independent samples). r Photograph depicting strong adherence of the Mg-ALN@Gel bone adhesive to a fragmented femur bone, capable of supporting a bucket filled with 5 L of deionized water. Three independent experiments were performed, and representative results are shown in (a, d, e, i, j, m, p, r). Data are presented as mean values ± SEM. The significance of differences was assessed using a two-sided Student’s t test with Tukey’s multiple comparison test. Source data are provided as a Source Data file.