Multifunctional Cu-doped Mn3O4 nanozyme hydrogel microspheres for oral targeted treatment of inflammatory bowel disease

Oral drug therapy for inflammatory bowel disease (IBD) is often hindered by inadequate targeting, low bioavailability, and reactive oxygen species (ROS) accumulation. To address these challenges, we have developed hydrogel microspheres@Cu-Mn 3 O 4 nanozymes (HMCM) by encapsulating hydrothermally synthesized Cu-doped Mn 3 O 4 nanozymes (CM NZs) into calcium alginate hydrogel microspheres (HM) using microfluidics. These microspheres are designed for colon-targeted IBD treatment. The CM NZs exhibit exceptional superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, effectively scavenging ROS such as H 2 O 2 , ·OH, and O 2 -· . The negatively charged HMCM promotes targeted accumulation in inflamed colon regions and facilitates specific nanozyme release. In a dextran sulfate sodium (DSS)-induced colitis mouse model, HMCM administration enhanced the expression of tight junction proteins (Claudin, ZO-1, Occludin) and repaired the damaged intestinal barrier. The oral HMCM group significantly reduced inflammation, enhanced antioxidant activity, and inhibited ferroptosis in colonic tissue through the upregulation of GPX4 and SLC7A11. It also restored gut microbiota balance by increasing probiotic populations and suppressing harmful bacteria. Systemic biosafety assessments confirmed HMCM's colon-specific retention and high biocompatibility. This research establishes HMCM as a precision-targeted colonic drug delivery platform, offering a promising therapeutic strategy for the treatment of inflammatory bowel disease. Calcium alginate hydrogel microspheres @ Cu-Mn 3 O 4 nanozymes (HMCM) were successfully synthesized. Due to their negatively charged surface, HMCM achieves site-specific enrichment in the colon and releases Cu-Mn 3 O 4 nanozymes (CM NZs), which exhibit antioxidant enzyme-like activity and reactive oxygen species (ROS) scavenging capacity. In a DSS-induced colitis mouse model, HMCM effectively treated IBD through a triple synergistic mechanism: enhancing antioxidant and anti-inflammatory activities, inhibiting ferroptosis in colonic tissue cells, and regulating gut microbiota. This work presents an efficient, targeted strategy for IBD therapy. • The synthesized Cu-Mn 3 O 4 nanozymes (CM NZs) exhibit stronger multi-enzyme mimicking activities (SOD, CAT, GPx) and free radical scavenging ability compared to Mn 3 O 4 NPs. • A colon-targeted composite of hydrogel microspheres@Cu-Mn3O4 nanozymes (HMCM) was engineered for precise oral nanozyme delivery. • HMCM treats IBD via a triple-synergistic mechanism. It simultaneously reduces inflammation and oxidative stress, inhibits ferroptosis by upregulating the GPX4 / SLC7A11 pathway, and beneficially reshapes the gut microbiota, collectively restoring intestinal homeostasis. • HMCM demonstrates excellent systemic biosafety and colon-specific retention.