Facile synthesis of Er3+/Tm3+ co-doped magnetic/luminescent nanosystems for possible bioimaging and therapy applications

Manganese-zinc ferrite is a kind of very important magnetic ferrite material. The properties of wide absorption band, sensitivity to ultraviolet (UV) light and tumor H 2 O 2 promise it to be possibly used as a photothermal therapy (PTT), photodynamic therapy (PDT) and chemodynamic therapy (CDT) agent. Based on the unique advantages of rare-earth doped nanoparticles , an Er 3+ , Tm 3+ co-doped upconversion-mediated nanosystem with manganese-zinc ferrite shell (named as UCNPS@M) was developed through a facile thermal co-decomposition method. The final nanosystems were surface-modified by using dopamine hydrochloride (DA) in order to warrant good biocompatibility (named as UCNPS@M@DA). Under irradiation of near-infrared (NIR) light, UCNPS emit both ultraviolet and visible light. The UV light is mostly absorbed by manganese-zinc ferrite shell to produce reactive oxygen species (ROS), which is essential to the potential PDT and CDT effect of nanosystems, and at the same time, Mn 0.5 Zn 0.5 Fe 2 O 4 can further react with H 2 O 2 to promote the efficiency of •OH-generation. It is expected that UCNPS@M@DA can act as upconversion luminescence imaging guidance due to the visible emission from UCNPS. In addition, the energy absorbed by the nanosystems can be transferred to heat to realize photothermal effect. Moreover, UCNPS@M@DA was successfully applied as a T 1 / T 2 -weighted magnetic resonance imaging (MRI) contrast agent due to the existence of Gd, Mn, and Fe elements. In light of the upconversion luminescence (UCL) imaging from the UCNPS as well as potential PTT, PDT, CDT effect mentioned above, this work provides a possibility to realize cancer multi-model bioimaging guided treatment by using an all-in-one diagnosis and therapy nanosystem through a simple yet powerful strategy.