Upconverting and persistent luminescent nanocarriers for accurately imaging-guided photothermal therapy.

The fluorescence-guided photothermal therapy (FPTT) has great potential in cancer treatment. However, the conventional FPTT has to be stimulated by external light, which tends to increase background noise and leads to the inaccurate infrared light irradiation for PTT. In this study, upconverting and persistent luminescent nanocarriers (UPLNs) loaded mesoporous silica nanoparticles (UPLNs@mSiO) were first designed to solve the problem mentioned above. The UPLNs cores can effectively reduce the short-lived autofluorescence interference by exerting the delay time between signal acquisition and pulsed excitation light. For testing the luminescence properties, the indotcyanine green (ICG) as photothermal agent was encapsulated into the UPLNs@mSiO. The experimental results showed that the UPLNs@mSiO nanoparticles could significantly reduce the short-lived autofluorescence interference and improve signal-to-noise ratio during FPTT. Our data suggest that UPLNs@mSiO may be a promising tool for improving the accuracy of PTT in vivo.