Fabrication and characterization of novel multifunctional superparamagnetic and fluorescent bioactive glasses for biomedical applications

Magnetic-fluorescent nanosystems have wide applications in the biomedical field due to their dual ability of unique biomolecular fluorescent recognition and magnetic modes. In this study fabrication of superparamagnetic-fluorescent bioactive glasses in the form of particle, nanofiber, and 3D scaffold was performed by the inclusion of maghemite (& gamma;-Fe2O3) nanoparticle and photoluminescent rare earth element ions (Eu3+, Gd3+, and Yb3+). Bioactive glasses in the form of particle, nanofiber, and 3D scaffolds were manufactured using sol-gel, electrospinning, and robocasting techniques, respectively. Morphological, structural, magnetic, and luminescence properties of the fabricated bioactive glasses have been investigated comprehensively using electron microscopy, x-ray diffractometer, vibrating sample magnetometer, Fourier transform infrared, and fluorescence spectrometers. The compressive strength of the robocast 3D glass scaffolds was measured. In vitro hydroxyapatite deposition on the surface of the bioactive glasses soaked in simulated body fluid for various times up to 28 days was also examined. Results showed that all of the bioactive glasses prepared in the study with different morphological characteristics have superparamagnetic properties. Saturation magnetization (Ms) values of the glasses were in the range of 7.20-12.50 emu/g. Additionally, all of the studied glass samples showed fluorescence behavior. The highest photoluminescence emission peak intensity was recorded for the Eu3+-doped robocast 3D glass scaffolds which is followed by nanofibrous and particulate forms of bioactive glass. Results of the in vitro bioactivity experiments showed that hydroxyapatite formation occurred on all of the bioactive glass samples and the highest hydroxyapatite formation rates were obtained for the fibrous glass samples due to their higher surface area.