Antibacterial and anti-biofilm activities of gold-curcumin nanohybrids and its polydopamine form upon photo-sonotherapy of Staphylococcus aureus infected implants: In vitro and animal model studies

Abstract

Implant-related infections are among the major post-surgery problems, and treatment of these infections is challenging due to the formation of biofilms by microorganisms such as Staphylococcus aureus. Herein, a novel gold-curcumin nanohybrid (GCNH) was synthesized for the first time and characterized. GCNH had a band gap energy of 2.41 eV, a zeta potential of −15 mV, and comprised uniform spherical particles with a mean diameter of 8 ± 2 nm. The biological macromolecule of polydopamine was then coated on GCNH to prepare a gold-curcumin-polydopamine nanohybrid (GCDNH). The nanohybrids were employed as novel dual photo-sonosensitizers for bacterial eradication by near-infrared (NIR) light and ultrasound (US) irradiations. GCNH and GCDNH represented photothermal conversion efficiencies of 26 and 32 %, respectively, and GCDNH represented a hemolysis rate of 2.3 % under both near-infrared (NIR) light and ultrasound (US) irradiations. NIR light and US irradiations (photo-sonotherapy) of Staphylococcus aureus using GCDNH depicted anti-bacterial and anti-biofilm efficiencies of 98 and 99 %, respectively, in synergistic manners, which are higher or as high as other sensitizers reported previously. The mechanism of photo-sonotherapy was related to generation of high levels of reactive oxygen species (ROS), and protein and nucleic acid leakages. In an in vivo infection model, NIR light and US irradiations annihilated Staphylococcus aureus on GCDNH-covered implants with high efficiency, without causing damage to normal tissues.