Hybrid bioink of methyacrylated starch with minimal methacrylated chitosan enables high-precision 3D printing for complex tissue scaffolds

Starch-based gels represent promising bioinks for 3D-printed cell scaffolds due to their biosafety, biocompatibility, and biodegradability. However, their widespread adoption has been hindered by inadequate formability and poor self-supporting properties. Here, we introduce an innovative starch-dominated hydrogel system achieved through dual methacrylation of normal corn starch and chitosan, enabling the fabrication of biodegradable cell scaffolds. While methacrylated starch alone (substitution degree: 0.013) exhibited insufficient printing accuracy even with UV assistance, the optimized 10:1 (starch/chitosan, w/w) blend of methacrylated chitosan (substitution degree: 0.27) demonstrated dramatically enhanced 3D printing formability and precision when combined with UV crosslinking. Rheological analysis demonstrated that blending methacrylated starch with methacrylated chitosan reduced flow stress (τ_f), improving printability while retaining shear-thinning behavior. Incorporation of 10 % glycerol enhanced biomacromolecular compatibility, as evidenced by rheological results and homogenous microstructures in SEM, enabling high-fidelity printing of intricate architectures. UV-cured scaffolds exhibited tunable compressive strength (150–200 kPa) and deformation rate (50–60 %), balancing mechanical compliance with tissue safety. The material's hydrophilic surface (contact angle: 30–60°) supported robust cell adhesion, while in vitro assays confirmed exceptional biocompatibility (96 % cell viability) and controlled biodegradation in α-amylase/lysozyme solutions. This work establishes starch as a primary matrix for bioinks, advancing sustainable, high-precision 3D printing in biomedicine.