Engineering of plasmonic metal-semiconductor yolk-shell nanostructures for multi-intensified photodynamic- and immuno- therapy against drug resistant bacteria

Photodynamic therapy (PDT) as well as immunotherapy are effective therapies to combat the systemic infection. Nevertheless, the development of the treatments are restrained by the lack of efficient photosensitizers (PS) and the genetic diversity of the bacteria. Here, we report Ag doped Au-CdS_1−ySe_y yolk-shell nanostructures (AYSs) which exhibit excellent near-infrared (NIR) light induced PDT and immunotherapy performance. The tailored plasmonic Au nanorods (NRs) are able to gather the NIR light, offering the basis for PDT. Moreover, high yield of reactive oxygen species (ROS) is achieved through the following creativity: i) enhanced light trapping ability by the microcavity, ii) smooth injection process of hot electrons (HEs) by the suitable band gap alignment, iii) inhibiting the combination of electric charges by the doped Ag with appropriate concentration. Therefore, the AYSs exhibit more 30 times of ROS production as well as lower 64 times of MIC than the conventional core-shell nanostructures. Notably, repeated enhanced antibacterial PDT are carried out to obtain versatile antigens from various dead bacteria to awaken the immune cells adequately and boost immune response with the help of Selenium (Se) which is distributed in the shell. As a result, the systemic drug resistant bacterial infection is cured successfully.