Three-dimensional Optical Coherence Thermometry Using Polymeric Nanogels.

In nanothermometry, the use of nanoparticles as thermal probes enables remote and minimally invasive sensing. In the biomedical context, nanothermometry has emerged as a powerful tool where traditional approaches, like infrared thermal sensing and contact thermometers, fall short. Despite the strides of this technology in preclinical settings, nanothermometry is not mature enough to be translated to the bedside. This is due to two major hurdles: the inability to perform three-dimensional thermal imaging and the requirement for tools that are readily available in the clinics. This work simultaneously overcomes both limitations proposing the technology of optical coherence thermometry (OCTh). This is achieved by combining thermoresponsive polymeric nanogels and optical coherence tomography (OCT) - a three-dimensional imaging technology routinely used in clinical practice. The volume phase transition of the thermoresponsive nanogels causes marked changes in their refractive index, making them temperature-sensitive OCT contrast agents. The ability of OCTh to provide three-dimensional thermal images was demonstrated in tissue phantoms subjected to photothermal processes, and its reliability was corroborated comparing experimental results with numerical simulations. The results included in this work set credible foundations for the implementation of nanothermometry in the form of OCTh in the clinical practice. This article is protected by copyright. All rights reserved.