Enhanced printability of high-viscosity chitosan/acrylamide inks via aluminum ions coordination for precision 3D bioprinting of scaffolds

Abstract

The primary limitation of 3D bioprinting remains in ink printability, which often necessitates the use of rheology modifiers or adjustments to the printing environment. Here, we introduce a novel method for preparing high-viscosity chitosan/acrylamide (CS/PAM) ink using an aluminum chloride (AlCl₃·6H₂O) solution as the solvent. The resulting hydrogel exhibits a compressive strength of 4.81 MPa and withstands 95 % strain without rupture. Experimental and simulation analyses demonstrate that Al³⁺ ions enhance the ink's printability, enabling the precise printing of complex structures. Additionally, by incorporating hydroxyapatite (HA) into CS/PAM ink, we developed a CS/PAM/HA scaffold, which significantly improved water retention and antibacterial properties, promoting enhanced dermal repair and epidermal regeneration in a rat skin defect model. This study showcases the potential of Al³⁺ dissolved CS/PAM ink for producing high-fidelity, complex scaffolds, providing a promising avenue for biomedical applications.