Nanocarriers for photodynamic-gene therapy.

The use of nanotechnology in medicine has important potential applications, including in anticancer strategies. Nanomedicine has made it possible to overcome the limitations of conventional monotherapies, in addition to improving therapeutic results by means of synergistic or cumulative effects. A highlight is the combination of gene therapy (GT) and photodynamic therapy (PDT), which are alternative anticancer approaches that have attracted attention in the last decade. In this review, strategies involving the combination of PDT and GT will be discussed, together with the role of nanocarriers (nonviral vectors) in this synergistic therapeutic approach, including aspects related to the design of nanomaterials, responsiveness, the interaction of the nanomaterial with the biological environment, and anticancer performance in studies in vitro and in vivo.

Assessment of synergism between enzyme inhibition of Cu/Zn-SOD and antimicrobial photodynamic therapy in suspension and E. coli biofilm.

BACKGROUND: Antimicrobial Photodynamic Therapy (aPDT) is a treatment based on the interaction between a photosensitizer (PS), oxygen and a light source, resulting in the production of reactive oxygen species (ROS). There are two main types of reactions that can be triggered by this interaction: type I reaction, which can result in the production of hydrogen peroxide, superoxide anion and hydroxyl radical, and type II reaction, which is the Photodynamic Reaction, which results in singlet oxygen production. Antioxidant enzymes (e.g., catalase and superoxide dismutase) are agents that help prevent the damage caused by ROS and, consequently, reduce the effectiveness of aPDT. The aim of this study was to evaluate a possible synergism of the combined inhibition therapy of the enzyme Cu/Zn-Superoxide dismutase (SOD) and the methylene blue- and curcumin-mediated aPDT against Escherichia coli ATCC 25922, in suspension and biofilm. METHODS: Kinetic assay of antimicrobial activity of diethydithiocarbamate (DDC) and Minimum Bactericidal Concentration (MIC) of DDC were performed to evaluate the behavior of the compound on bacterial suspension. Inhibition times of Cu/Zn-SOD, as well as DDC concentration, were evaluated via bacterial susceptibility to combined therapy in suspension and biofilm. RESULTS: DDC did not present MIC at the evaluated concentrations. The inhibition time and Cu/Zn-SOD concentration with the highest bacterial reductions were 30 minutes and 1.2 µg/mL, respectively. Synergism occurred between DDC and MB-mediated aPDT, but not with CUR-mediated aPDT. CONCLUSIONS: The synergism between Cu/Zn-SOD inhibition and aPDT has been confirmed, opening up a new field of study full of possibilities.