(1) Abstract: 

This study constructs a biomimetic probiotic platform, OSM, by loading outer membrane vesicles derived from Escherichia coli Nissle 1917 into bicontinuous ordered mesoporous metal-phenolic networks, followed by encapsulation in ascorbyl palmitate hydrogel to form OSMA. The platform mimics probiotic vesicle secretion and colon colonization behavior for the prevention and treatment of ulcerative colitis.

(2) Background: 

Ulcerative colitis is a chronic relapsing intestinal inflammatory disease, and conventional drugs have limited targeting. Probiotics can regulate microbiota, immunity, and the intestinal barrier, but live bacteria carry risks of translocation and bacteremia. Probiotic-derived vesicles are easily diluted and degraded by reactive oxygen species at inflamed sites, limiting oral delivery efficacy.

(3) Main Content: 

SP-MPNs are formed by catechol-Fe³⁺ coordination and feature continuous open channels, high specific surface area, and antioxidant capacity, enabling vesicle loading and protection. Transferrin at inflamed sites competes for Fe³⁺, triggering slow vesicle release; catechol groups interact with mucin to prolong colonic retention. OSM exhibits antioxidant, anti-inflammatory, and immunomodulatory activities.

(4) Study Design: 

Material synthesis and structural characterization, vesicle loading and release, antioxidant and enzyme-like activity, cell protection, macrophage polarization, mucin binding, and colon targeting were evaluated. A DSS-induced colitis mouse model was established for preventive and therapeutic administration, with colonoscopy, histology, immunofluorescence, cytokines, 16S rRNA sequencing, and transcriptomics.

(5) Results: 

OSMA resisted gastric acid and targeted the inflamed colon, prolonging vesicle retention. The system scavenged reactive oxygen species, promoted macrophage transition from M1 to M2, reduced pro-inflammatory cytokines and increased anti-inflammatory cytokines, repaired tight junctions and the mucus layer, modulated gut microbiota and the tryptophan-IPA-AhR-IL-22 pathway, and alleviated colonic injury.

(6) Future Directions: 

Further validation in multispecies and chronic models is needed to clarify the causal relationships among material structure, vesicle release, and immune-metabolic regulation. Long-term safety, batch consistency, and dosing regimens should be assessed, and the dynamic interactions between the biomimetic platform, host microbiota, and intestinal barrier should be dissected.

We provide full-process services for various material designs (including highly innovative scheme design, preparation, characterization, in vitro and in vivo validation (cell/animal experiments), etc.): a postdoctoral team (with multiple high-impact publications in Zone 1 journals) can meet all kinds of tricky and challenging requirements, including hydrogels / drug delivery / nanomaterials / polymers / liposomes / microneedle drug delivery, etc. We can assist with project design / NSFC grant applications / publication of high-impact Zone 1 and Zone 2 papers in journals such as AFM, SCI, AM, etc. Welcome to consult 👇️
17768014569 (Senior Engineer Gao)
17761925168 (Engineer Zhang)
18013729810 (Engineer Yang)