FIGURE 3.

Schematics of (a) two opposing aggrecan macromolecules undergoing interpenetration and entanglement in vivo; (b) network structure between aggrecan via self-adhesion due to Ca²⁺-mediated ion-bridging and molecular entanglements between GAG chains, and energy dissipation of the Ca²⁺-ion-bridges upon mechanically induced GAG molecular elongation (not drawn on scale); and (c) possible hydrogen bonding (dashed arrows), hydrophobic interaction (could occur between the methyl groups and carbon rings), and Ca²⁺-mediated ion-bridging between CS-GAG chains in the presence of water molecules. Water bridges could exist between the hydrogen bonding donors and acceptors.