Microenvironment-Responsive Multifunctional Enzyme-Linked Hydrogel for Diabetic Bone Defects Regeneration

Diabetes mellitus (DM) bone defects face impaired healing due to hyperglycemia, chronic inflammation, and dysregulated bone remodeling, yet existing therapies lack comprehensive strategies targeting these interconnected issues. To address this, a glucose/ROS-responsive multifunctional hydrogel (AAT-ZCG) was designed, integrating tannic acid (TA)-mediated dynamic borate ester bonds and a cascade nanozyme comprising cerium-zoledronic acid-glucose oxidase (ZCG). The hydrogel enables stimuli-responsive release of TA and ZCG within DM microenvironments, depleting glucose via glucose oxidase-mediated catalysis and mitigating inflammation through cerium-mediated ROS scavenging. Moreover, ZCG modulates macrophage polarization, stimulates angiogenesis and enhances osteogenesis. Acidic byproducts trigger ZCG degradation, releasing zoledronic acid to inhibit excessive osteoclast activation. Transcriptomic analysis revealed upregulated forkhead box O1 transcription factor, a key regulator of bone metabolism and inflammation. This all-in-one platform concurrently addresses pivotal mediators in DM bone defects, overcoming limitations of single-target approaches. By consolidating multifunctional responses, AAT-ZCG provides a concise yet effective strategy for DM bone defect regeneration. RNA was extracted from BMSCs used for osteogenic differentiation experiments in vitro from the control and AAT-ZCG groups. All samples underwent quality control. RNA-seq were performed by a sequencing company (Chi Biotech, Shenzhen, Guangdong, China), which also delivered the initial analysis report. Statistical significance was set at P < 0.05, with a fold change of >2 or <0.5 determining significantly differentially expressed genes (DEGs). These DEGs and different metabolites were then subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses.