Up-down conversion luminescence and drug-loading capability of novel MoO3-x based carriers

Abstract A new rod-shaped MoO3-x@YF3:Yb3+,Er3+ integrated carrier for the NIR-II fluorescence imaging and chemotherapy has been successfully prepared by introducing the local surface plasmon resonance (LSPR) effect and regulating the morphology and surface state. The analysis methods such as XRD, SEM, EDX, TEM, UV–Vis-NIR, PL and IR are used to study the structure, morphology, composition and properties. XRD, SEM and TEM analysis shows that the surface of MoO3-x is successfully coated with YF3:Yb3+, Er3+ nanocrystals of well-crystallized orthogonality, and the carrier obtained has a unique rod-like morphology. XPS analysis shows that Mo element exists in two valence states: Mo (VI) and Mo (V). Furthermore, PL analysis shows that the carrier has stronger luminescence intensity of up-conversion and the near-infrared second region (NIR II) under the excitation of 980 nm and 1540 nm, respectively. The drug delivery capacity and release effect of carrier are studied by using doxorubicin (DOX) as an anti-tumor template drug. The results shows that the carrier with unmodified polyethylene glycol (PEG) has strong drug loading capacity and release effect. The cytotoxicity of the carrier is performed using Hela cells. The result show that the cytotoxicity was obviously related to the concentration of MoO3-x@YF3:Yb3+,Er3+ nanoparticles. This work will solve the bottleneck of fluorescence imaging of visual drug delivery carriers, tumor penetration rate and efficient drug delivery.