Three-dimensional (3D) bioprinting constitutes a groundbreaking approach for constructing biomimetic tissue structures, holding substantial promise for tissue engineering and regenerative medicine. A key obstacle, however, lies in creating environmentally sustainable bio-inks that deliver strong printability, robust mechanical performance, and long-term stability in physiological environments, all while avoiding expensive and laborious chemical alterations. This research introduces a practical and sustainable physically crosslinked gelatin-based bio-ink, termed Gel-X, which incorporates gelatin, gellan gum, and Laponite XLG to support multi-modal bioprinting. The Gel-X formulation is assembled rapidly and simply (∼1 h) by mixing the polymers in deionized water, without any chemical crosslinking agents. This results in markedly better printability, enhanced mechanical characteristics, and improved control over degradation and shape retention. The inclusion of Laponite XLG particularly reinforces the gel matrix, promoting greater structural stability and mechanical durability during extended periods. Experimental outcomes confirm that cell-laden Gel-X constructs preserve their form and strength in physiological settings, successfully countering the fast breakdown and weak mechanics common in traditional physically crosslinked bio-inks. In addition, Gel-X constructs show excellent cell compatibility, allowing the production of intricate and durable 3D architectures for bioprinting purposes. By dispensing with chemical crosslinkers, the Gel-X bio-ink represents an eco-friendly advancement for sophisticated multi-modal bioprinting. This development resolves longstanding issues in bio-ink engineering and significantly improves the reach and effectiveness of 3D bioprinting technologies.
