Biofilm- and Spore-Disruptive Star-Shaped Poly( l -lysine)/Hyaluronic Acid Microgels for Targeted Oral Therapy of Clostridioides difficile Infection

Clostridioides difficile infection (CDI) remains a major healthcare challenge due to recurrent disease, spore persistence, and biofilm-associated tolerance, while conventional antibiotics often disrupt gut microbiota. Here, we report a star-shaped poly(l-lysine) dendrimer (G3-PLL9) formulated into hyaluronic acid-based microgels for targeted oral delivery to the inflamed colon. G3-PLL9 exhibited potent antimicrobial activity, including rapid bactericidal effects, superior spore inhibition compared with vancomycin, and robust biofilm disruption at subinhibitory concentrations. In a murine CDI model, rectal administration of G3-PLL9 alleviated clinical symptoms, reduced tissue damage, and lowered recurrence risk. To enable oral therapy, G3-PLL9 was incorporated into hyaluronic acid microgels, achieving site-specific release through hyaluronidase-mediated degradation in the inflamed colon. Importantly, treatment preserved commensal gut microbiota more effectively than vancomycin. Collectively, these findings highlight G3-PLL9 microgels as a microbiota-sparing therapeutic that targets multiple stages of CDI pathogenesis─including spores and biofilms─and demonstrate their potential for clinical translation.