Fiber Bragg Grating Sensors-Based Thermometry of Gold Nanorod-Enhanced Photothermal Therapy in Tumor Model

This work proposes the use of femtosecond laser-written fiber Bragg grating (FBG) sensors for internal temperature monitoring of tumors undergoing gold nanorod (AuNR)-mediated photothermal therapy (PTT). Arrays of sub-millimetric FBGs enabled an accurate and quasi-distributed temperature measurement within subcutaneous breast tumors in mice. Furthermore, FBGs permitted to investigate the laser-tissue interaction and AuNR-assisted photothermal enhancement on cancerous tissue exposed to 940 nm and 1064 nm radiations. The introduction of the tumor-localized AuNRs resulted in an overall increase of 13 °C of the mean temperature change, compared to control, in case of 1064 nm, while ~6 °C in case of 940 nm. This sensing solution allows the minimally invasive measurement of the internal tumor temperature under AuNR-assisted PTT. This feasibility study sets the basis for the evaluation of the thermal outcome mediated by nanoparticles under different laser sources.