Multifunctional Hydroxyapatite Nanofibers and Microbelts as Drug Carriers

Luminescent, mesoporous, and bioactive europium-doped hydroxyapatite (HAp:Eu3+) nanofibers and microbelts have been prepared by a combination of sol-gel and electrospinning processes with a cationic surfactant as template. The obtained multifunctional hydroxyapatite nanofibers and microbelts, which have mesoporous structure and red luminescence, were tested as drug carriers by investigating their drug-storage/release properties with ibuprofen (IBU) as model drug. X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution (HR) TEM, FTIR spectroscopy, N-2 adsorption/desorption, photoluminescence (PL) spectra, and UV/Vis spectroscopy were used to characterize the structural, morphological, textural, and optical properties of the resulting samples. The results reveal that the multifunctional hydroxyapatites exhibit irregular mesostructure, and have fiber-like and beltlike morphologies with sizes of several hundred nanometers in width and several millimeters in length. The IBU-loaded HAp:Eu3+ system shows red luminescence of Eu3+ (D-5(0)-F-7(0.1,2)) under UV irradiation and controlled release of IBU. In addition, the emission intensity of Eu3+ in the drug carrier system varies with the released amount of IBU, and thus drug release can be easily tracked and monitored by the change in luminescence intensity.