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

- UPLNs@mSiO2 could significantly reduce short-lived autofluorescence interference.
- UPLNs@mSiO2 could improve signal-to-noise ratio during photothermal therapy.
- UPLNs@mSiO2 may improve the accuracy of photothermal therapy for cancer in vivo.

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@mSiO2) 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@mSiO2. The experimental results showed that the UPLNs@mSiO2 nanoparticles could significantly reduce the short-lived autofluorescence interference and improve signal-to-noise ratio during FPTT. Our data suggest that UPLNs@mSiO2 may be a promising tool for improving the accuracy of PTT in vivo.

The imaging and photothermal property of (ICG + UPLNs)@mSiO2 nanoparticle in vivo. The persistent luminescence in the first line, the upconverting imaging (MDL-N-980) in the second line, and the photothermal imaging in the third line for different sample.316