ACTA POLONIAE PHARMACEUTICA, cilt.79, sa.2, ss.255-266, 2022 (SCI-Expanded)
Due to the significant loss in the effectiveness of conventional antibiotics against MDR bacterial strains, effective antibacterial therapy strategies are urgently needed. The aim of this study is to design a novel theranostic IR780 encapsulated, nanosized, radiolabeled ethosomes for effective Photodynamic (PDT)/photothermal therapy (PTT) and concurrent imaging of infections and to assess the role of the surface charge of theranostic ethosomes on effectiveness. Low aqueous solubility, ROS yield, and penetration ability of IR 780 can be enhanced by encapsulation in ethosomes, and also concurrent imaging can be achieved by designing nanotheranostic ethosomes. IR780 encapsulated, Tc-99m-labeled, neutral IR780-PL100H:PEG2000:DTPA-PE and positively charged IR780-PL100H:SA:PEG2000:DTPA-PE ethosomes were designed for scintigraphic and near-infrared (NIR) imaging and PDT/PTT of bacterial infections. Their characterization and in vitro release profiles were determined. The physical stability of formulations was evaluated for 3 months at 25 degrees C and 4 degrees C. Their thermal performance and antibacterial activity against S. aureus and E. coli were evaluated by NIR irradiation (808 nm, 1 Wcm(-2)) for 2 min. Ethosomes exhibited suitable particle sizes (similar to 200 nm, PDI: 0.12), zeta potentials (-25 to -28mV), encapsulation efficiencies (81-84%), release profiles, and found stable for 1 month at 4 degrees C. Both ethosomes exhibited significant thermal enhancements by NIR light application. Although neutral ethosomes showed a potent antibacterial effect, positively-charged IR780-PL100H:SA:PEG2000:DTPA-PE exhibited higher PDT/PTT antibacterial efficacy against S. aureus and E. coli under NIR irradiation. Therefore, IR780 nanotheranostic ethosomes were found potentially effective for imaging, and PDT/PTT antibacterial and positive surface charge could contribute to higher PDT/PTT antibacterial efficacy.