Electrospinning fabrication of SrTiO3:Er3+ nanofibers and their applications of upconversion properties

SrTiO3:Er3+ nanofibers were fabricated by the electrospinning process. The phase, microstructure, Doxorubicin loading and release properties, as well as upconversion emission of the fabricated SrTiO3:Er3+ nanofibers were investigated. The X-ray diffraction patterns indicate that the SrTiO3:Er3+ nanofibers have the pure cubic phase. The images of scanning electron microscopy and transmission electron microscopy demonstrate that nanofibers with a porous structure have been obtained. The SrTiO3:Er3+ nanofibers can be used in drug delivery system, which is confirmed by the Fourier transform infrared spectra, results of Barrett Emmett Teller measurements and thermogravimetry. Under 808 nm light irradiation, the release process of Doxorubicin in SrTiO3:Er3+ nanofiber shows close relation with the pH value. An acidic condition increases the solubility of the Doxorubicin for the protonated daunosamine group, which accelerates and improves the release of Doxorubicin in SrTiO3:Er3+ nanofibers. In addition, the degree of Doxorubicin release can be manifested by the changing intensity of upconversion emission.