Nanostructured Gd$_2$O$_3$:Yb micropowder for antibacterial hyperthermia

A method has been proposed for photoinduced hyperthermia of pathogenic Gram-negative bacteria P. aeruginosa using Gd$_2$O$_3$:Yb micropowder. It is based on the possibility of laser excitation of anti-Stokes luminescence on ytterbium ions in the gadolinium oxide micropowder, which allows us, on the one hand, to heat the powder to the required temperature and, on the other hand, to accurately control the powder temperature using remote luminescent thermometry. It has been demonstrated that the long-term irradiation of the Gd$_2$O$_3$:Yb micropowder with 1035-nm nanosecond laser radiation changes the shape of anti-Stokes luminescence spectra associated with micropowder heating in the range from 27 to 63$^\circ$C. The application of the proposed photoinduced hyperthermia method to a mixture of solutions of the Gd$_2$O$_3$:Yb micropowder and P. aeruginosa bacteria demonstrates a decrease in the bacterial population by 90%.