Bacteria‐Targeting Photodynamic Nanoassemblies for Efficient Treatment of Multidrug‐Resistant Biofilm Infected Keratitis

Abstract Multidrug‐resistant Pseudomonas aeruginosa (MDR‐ P. aeruginosa ) cannot be extirpated with any of the antipseudomonal antibiotics available in clinic because P. aeruginosa exhibit natural resistance to antibiotics and form a stable biofilm. Biofilm formed by P. aeruginosa is a leading cause of bacterial keratitis which may cause corneal perforation and even blindness. Antibacterial photodynamic therapy (aPDT) is a promising bactericidal method in combatting drug‐resistant bacteria. Unfortunately, the use of broad‐spectrum aPDT that kills bacteria indiscriminately may lead to microbiota imbalance and cause serious side effects in normal cells. Herein, PαGal 50 ‐b‐ PGRB 20 , which can effectively disperse biofilms and selectively kill MDR‐ P. aeruginosa inside biofilms by binding to Lec A in the extracellular polymeric substances and on the P. aeruginosa membrane with low phototoxicity caused by broad‐spectrum aPDT, is designed and synthesized. PαGal 50 ‐b‐ PGRB 20 has bactericidal activities by damaging DNA, RNA, protein, and membrane. In vivo study of the MDR ‐P. aeruginosa biofilm infected keratitis model demonstrates the potential of PαGal 50 ‐b‐ PGRB 20 for a better corneal recovery. This work provides a dedicated antibacterial material for preferentially killing MDR‐ P. aeruginosa over normal cells and other bacteria.