Erythrocyte membrane-camouflaged magnetic and up/downconverting nanoparticles for photothermal therapy and luminescent nanothermometry

Abstract

Cell-membrane-coated nanoparticles (NPs) have important applications in the prevention, diagnosis, and treatment of diseases. Here, we demonstrate the preparation of a multifunctional membrane camouflage system consisting of Zn-Mn ferrite and rare-earth (Nd, Yb, and Ho)-doped fluoride NPs encapsulated into the red blood cell membrane (RBCm). Energy-dispersive spectroscopy and transmission electron microscopy of the RBCm showed the encapsulation of the magnetic and fluorescent fluoride NPs. The magnetic properties of the nanocarrier showed superparamagnetic behavior as a result of the ferrite NP and diamagnetic contribution as a result of the membrane constituents. Magnetic nanoparticle hyperthermia was found to have a lower efficiency compared to photothermal therapy (PTT) under the conditions evaluated. The photothermal conversion efficiency is found to be around 13% (excitation at 808 nm). MNH and PTT properties arise from the magnetic NPs, while the luminescent properties arise from the rare-earth-doped fluoride NPs. The Nd ions in the fluoride NP are excited at 808 nm, avoiding nonspecific tissue heating. Down-conversion peaks are related to Nd/Yb emissions, whereas upconversion peaks arise from Ho states as a result of energy transfer processes. Potential multiparametric luminescence thermometry based on the emission of Yb3+/Nd3+ intensity ratio (980/1060 nm) provides encouraging results for real-time monitoring of thermal therapy in the second biological window. The thermal sensitivity ranged from 0.58 to 0.62%K−1 at the range of 45–60 °C.