Synchronous Sterilization and Immunoreaction Termination for Corneal Transparency Protection in Treating Pseudomonas aeruginosa Induced Bacterial Keratitis

In the treatment of infectious keratitis, therapeutic strategies often prioritize enhancing bactericidal efficacy. However, endotoxins released from Gram-negative bacteria cause inflammatory reaction, leading to corneal structural damage and scar formation. Given that polymyxin B (PMB) can bind and neutralize lipopolysaccharide (LPS), this study employs large-pore mesoporous silica nanoparticles (lMSNs) grafted with PMB as carriers for cationic antibacterial carbon quantum dots (CQDs) to prepare CQD@lMSN-PMB, which enables synchronous sterilization and endotoxin neutralization. In the acidic infectious microenvironment, the accelerated release of CQDs eliminates 99.88% bacteria within 2 h, effectively substituting immune mediated sterilization. Notably, CQD@lMSN-PMB exhibits exceptional LPS neutralization performance (2.22 µg LPS/mg CQD@lMSN-PMB) due to its high specific surface area. In an infectious keratitis model, inflammation subsides significantly within the first day of CQD@lMSN-PMB intervention and is completely resolved by day 3. By day 2, interleukin-1β, interleukin-6 and tumor necrosis factor-α in CQD@lMSN-PMB group decrease by 86.99%, 91.15%, and 77.56%, respectively, compared to the CQDs-only sterilization group. Ultimately, corneal integrity and transparency are preserved, with suppressed expressions of fibrosis-related factors including matrix metalloproteinase 9, transforming growth factor-β and α-smooth muscle actin. Therefore, this synchronous sterilization and endotoxin neutralization strategy outperforms monotherapy strategies focused solely on sterilization or endotoxin neutralization.