Injectable foam-like scaffolds release glucose oxidase-integrated metal–organic framework hybrids for diabetic bone defects

Diabetic bone defect repair remains a significant clinical challenge due to the impact of glucose fluctuations, reactive oxygen species (ROS) damage, and the inflammatory microenvironment, all of which impede the normal bone repair process. In this study, we have developed a biological scaffold material aimed at localized regulation of the diabetic microenvironment within bone defect sites. Our approach involves the creation of an injectable, UV-curable, gas-foamed multifunctional hydrogel, incorporating methacrylic anhydride gelatine (GelMA) and hydroxyapatite nanowires (HAP NWs). This hydrogel is further enhanced with Gallic acid and magnesium ion (Mg²⁺) metal-organic frameworks (MOF) loaded with glucose oxidase (GOx), forming the GOx-MOF/HAP-GelMA composite. It can be injected and immediately cured to assume various customized shapes, while maintaining desirable hardness. It's noteworthy that the controlled release of Gallic acid within GOx-MOF actively engages in a cascade reaction, efficiently eliminating the H2O2 generated by GOx-catalyzed glucose decomposition, thus optimizing the benefits of GOx while minimizing potential harm. The developed composite demonstrates remarkable capabilities in blood sugar regulation, ROS elimination, inflammation modulation, and the facilitation of osteogenesis and angiogenesis. This study represents a major step in precisely controlling the microenvironment for diabetic bone regeneration and provides a minimally invasive solution for addressing bone defects.