Multifunctional mussel-inspired gelatin methacryloyl hydrogels for infection-sensitive applications

• Injectable, mussel-inspired GelMA hydrogels with smart pigments enable real-time infection color change. • The multifunctional hydrogel system enables the loading and release of antimicrobial agents to inhibit bacterial infections. • The nanocomposite hydrogel stimulates angiogenesis and vascular tubule formation. • The nanocomposite hydrogel patches outperform conventional sterile gauze pads in exudate absorption and hemostasis. Bacterial infections remain a major health concern, with early and accessible detection critical for effective intervention. Here, we introduce a multifunctional and biocompatible gelatin methacryloyl hydrogel designed for real-time visual monitoring and localized antimicrobial action. The system incorporates bromothymol blue (BTB) encapsulated within pH-responsive smart pigments, enabling a controlled colorimetric shift from yellow to blue in response to basic microenvironments generated by Gram-negative bacteria. In vitro studies using Escherichia coli validate the platform’s utility for rapid infection detection. Catechol functionalization enhances the hydrogel’s mechanical strength and mussel-inspired adhesion, supporting appropriate contact with infection-prone surfaces. As a proof of concept for therapeutic integration, zinc oxide (ZnO) nanoparticles were embedded to demonstrate the hydrogel’s capacity for antimicrobial agent loading and release. This integrated, easy-to-use material provides a promising strategy for simultaneous detection and treatment of bacterial infections, especially in resource-limited or point-of-care settings.