Optically stimulated heating using Nd3+ doped NaYF4 colloidal near infrared nanophosphors

Although efficient in heat generation, gold nanoparticles dedicated for photostimulated localized hyperthermia treatment (LHT) lack luminescent properties suitable for detection in heterogeneous and autofluorescent tissue. Here, we study and report the use of bifunctional luminescent neodymium (Nd3+) ions doped α-NaYF4 colloidal nanoparticles as potential nanoheaters suitable for LHT. Up to 35°C (0.8°C/mW@514.5 nm) temperature rise in ∼0.5 ml colloidal 25%Nd3+:NaYF4 solution was achieved in comparison to around a 4°C rise for the undoped colloidal NaYF4. The maximum temperature (T max ) was linearly proportional to the concentration of Nd3+ dopant. The time required to elevate temperature to 1/e×T max varied from 100 to 135 seconds. The proposed approach gives premises to the construction of multi-functional therapeutic agents detectable by means of fluorescence molecular imaging.