Theranostic Nanocapsules: Heating, Imaging, and Luminescence Nanothermometry

We report a theranostic nanocapsule, working entirely in the near-infrared (NIR) region for photothermal therapy (PTT) with the ability to remotely record the temperature in real time. These nanocapsules are synthesized by a one-pot approach, simultaneously coencapsulating bay-substituted dicyclohexylaminoperylene diimide (sPDI) as an optical heater and rationally designed multifunctional LiLuF4:10 mol % Nd3+@LiLuF4 core@shell downshifting NPs (DSNPs), as both ratiometric luminescent thermometers and imaging probes. Upon laser irradiation, the sPDI aggregates convert light to heat via nonradiative relaxation, inducing a local temperature increase and eradicating MCF-7 breast cancer cells. Accurate temperature sensing is achieved in situ by the luminescence of the DSNPs. In addition, a positive contrast enhancement is found in the computer tomography (CT) images of the cancer cells under investigation, owing to the presence of Lu3+ in the DSNPs, demonstrating the potential for image-guided PTT.