ROS-responsive Ag-TiO2 hybrid nanorods for enhanced photodynamic therapy of breast cancer and antimicrobial applications

Abstract

There has been significant interest in designing heterostructured nanoparticles with excellent synergistic properties and multifunctionality. Herein, this work reports on the design of reactive oxygen species- (ROS-) responsive Ag decorated TiO2 hybrid nanorods (HNRs) with dual functionalities of enhanced photodynamic therapy and antibacterial activity. A de-wetting phenomenon was employed to nucleate and crystallize Ag nanoparticles onto the surface of TiO2 nanorods resulting in Ag-TiO2 hybrid nanocomposites. The use of the Pluronic® F-127 polymer, which is permitted by the Food and Drug Administration (FDA), remarkably improved the biocompatibility of Ag-TiO2 HNRs tested in 4T1 breast cancer cells. Furthermore, Ag-TiO2 HNRs endocytosed by cancer cells produced high intracellular ROS under UV conditions (5.6 mW cm−2), resulting in cancer cell apoptosis. Similarly, the distinctive features of Ag NPs on TiO2 nanorods slow down the recombination rate of electrons–holes, and exhibited 90% killing efficacy against Escherichia coli (gram-negative/rods) and Staphylococcus aureus (gram-positive/cocci). The potential of photo-activated Ag-TiO2 HNRs, as demonstrated in this work, indicates that this heterostructured material is a promising novel dual-therapeutic strategy against cancer cells and microbial agents.