Bacterial infections and related complications are predominantly responsible for the failure of artificial biomaterials assisted tissue regeneration in clinic. In this work, a hybrid surface system is applied to prolong the drug release duration from dug-loaded titania nanotubes and thus to prevent Ti implants-associated bacterial infections. This feature is endowed by conjugating folic acid (FA) onto the surface of ZnO quantum dots (QDs)-NH2 via an amidation reaction. Titania nanotubes (TNTs) loaded with vancomycin (Van) are capped by these FA functionalized ZnO (ZnO-FA) QDs that keep stable in normal physiological environments but dissolves to Zn2+ in the mildly acidic environment after bacterial infections as validated by the drug release profile. The antibacterial ratio of TNTs-Van@ZnO-FA QDs against Staphylococcus aureus is enhanced from 60.8% to 98.8%while this value is only increased from 85.2% to 95.1% for TNTs-Van once the pH value of the environment is decreased from 7.4 to 5.5. This is due to the synergistic effects of Van and Zn2+ because the gradual dissolution of ZnO-FA caps on TNTs with the decrease of pH value can induce the acceleration of both Van and Zn2+ release. In addition, this TNTs-Van@ZnO-FA system also exhibits excellent biocompatibility because of the folic acid and sustained release of Zn ions. Hence, this surface system can be potentially used as a promising bioplatform on Ti-based metallic implants to prevent bacterial infection with a long-lasting effect.
Keywords: Antibacterial; Drug delivery; Infection prevention; Quantum dots; ZnO; pH sensitivity.
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