Biomaterial-based microbiota strategies for targeting the intestinal immune microenvironment in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract with an unclear etiology. Its onset and progression are closely associated with gut microbiota dysbiosis and immune dysfunction. Microbiota-based therapeutic strategies can alleviate intestinal inflammation to some extent. However, their clinical efficacy remains limited due to challenges during delivery, including degradation by gastrointestinal components, insufficient exposure of active agents, and unstable colonization in the colon. This review systematically summarizes various biomaterial-based microbiota strategies, including probiotics, prebiotics, synbiotics, postbiotics, fecal microbiota transplantation, and bacteriophage therapy. Particular emphasis is placed on the critical role of biomaterials in enhancing the stability of microbiota-modulating agents, achieving colon-targeted release, and improving local retention at the intestinal mucosa. Furthermore, considering the coordinated regulation of the gut microbiota and immune cells in IBD pathogenesis, this review highlights four key immune cell types: macrophages, neutrophils, dendritic cells, and T lymphocytes. Recent advances are summarized on how microbiota-modulating delivery systems restore gut microbial and immune homeostasis by modulating the functional states of these immune cells, primarily through colon-targeted delivery, inflammation-site enrichment, and local retention of microbiota-modulating agents. Additionally, the potential applications of these biomaterials in other intestinal diseases are discussed, providing a comprehensive reference for the research and application of biomaterial-based microbiota strategies in intestinal diseases.