UCNP@SiO₂-maltotrios/HMME preparation and properties study

Bone and joint infections (BJI) are common diseases in the musculoskeletal system, posing significant challenges due to their difficult early diagnosis, prolonged treatment periods, high costs, and potential for severe consequences. Building upon our previous work on maltotriose-modified magnetite nanoparticles (Fe₃O₄-maltotriose), we delve deeper into the research, incorporating the photosensitizer HMME. This integration enables targeted diagnosis of infectious lesions while simultaneously killing bacteria for therapeutic intervention. This study presents the development of a precision drug delivery system (UCNP@SiO₂-maltotrios/HMME) for the treatment of bacterial infections in bones and joints. Through a microemulsion method, we encapsulated mesoporous SiO₂ onto the surface of upconversion nanoparticles (UCNPs). We then loaded the internal space with the photosensitizer porphyrin monomethyl ether (HMME) to release singlet oxygen (¹O₂) upon acoustic activation, and externally loaded maltotriose (maltotrios) as a targeting molecule. Our research investigates the HMME drug loading capacity, and singlet oxygen bactericidal capabilities of this material using a rat infection model. We further evaluated its bactericidal efficacy and biosafety through in vitro cell experiments and in vivo animal studies. Our results demonstrate the excellent luminescence properties and normal imaging capabilities of UCNP@SiO₂-maltotrios/HMME both in vitro and in vivo. Notably, this material exhibits strong precision targeting and antibacterial activity against Escherichia coli and Staphylococcus aureus. Moreover, UCNP@SiO₂-maltotrios/HMME demonstrates no cytotoxicity in cells or organs of mice, indicating its favorable biosafety.