Surface functionalization of YVO₄ nanoparticles with cucurbit[n]uryls: potential hybrid systems for thermal sensing in photodynamic therapy

Full text: Luminescent lanthanide-based nanomaterials have been widely applied in sensing and diagnostic studies due to their unique optical properties [1,2]. For instance, such nanoparticles can act as optical thermometers, which can be applied as in situ thermal sensors in photodynamic therapy. As thermal regulation plays a mandatory role in this type of treatment, the use of luminescent thermometers can provide significant improvement to this field. In this sense, this work aims to functionalize the surface of YVO₄:Ln³⁺ (Ln=Eu³⁺, Yb³⁺/Er³⁺) with cucurbit[n]uryls (CB[6] or CB[7]) for further attachment of photodynamically active dyes[3]. For this, YVO₄:Ln³⁺ nanoparticles were firstly obtained via colloidal conversion of hydroxy carbonates [2] or via a citrate-mediated hydrothermal synthesis. Functionalization with CB[n] was accomplished by a wetness impregnation methodology. X-ray diffractometry, infrared spectroscopy, dynamic light scattering, and pH x ζ potential analyses confirmed the surface interaction between the nanoparticles and the macrocycles. The obtained systems displayed downshift and up conversion luminescence that can be potentially applied for optical thermometry. Further studies comprising attachment of active organic dyes will be used to confirm the applicability of the YVO₄:Ln³⁺@CB[n] systems in photodynamic therapy. References: 1] Liu, B. et al.; Adv. Mater., 29, 160434, 2017. [2] de Sousa Filho, P.C. et al.; J. Phys. Chem. C, 123, 2441, 2019. [3] Francés-Soriano, L. et al.; Nanoscale, 7, 5140, 2015. (author)