Nanoparticles for Biomedical Applications Prepared by CO2 Laser Vaporization

摘要

Functional ceramic nanopowders with emphasis on biomedical applications were engineered by gas-phase condensation using the CO2 laser vaporization (LAVA) technique. Europium doped strontium aluminate nanoparticles (NP) were prepared from a SrO/α-Al2O3/'Eu2O3 powder mixture. Excited with ultraviolet radiation (UV), the as-prepared amorphous NP revealed red photoluminescence emission. After annealing in reductive atmosphere crystalline SrAl2O4:Eu~(2+) nanopowder was obtained showing strong green emission at UV excitation. Ferrimagnetic iron oxide (Fe_xO_y) nanopowders were prepared starting from α-Fe2O3 powder. In oxygen-free condensation atmosphere γ-Fe2O3 NP were obtained. Oxygen as condensation gas yielded γ- and ε-Fe2O3 NP. Superparamagnetic NP were prepared starting from α-Fe2O3/SiO2 mixtures. Depending on the mixing ratio γ-Fe2O3 nanocrystallites embedded in a SiO2 glass matrix or γ-Fe2O3-SiO2 Janus NP were obtained. These NP provide a reactive SiO2 interface for subsequent functionalizing. The co-vaporization of α-Al2O3 as the main proportion and t-ZrO2 yielded zirconia-toughened-alumina NP. Reinforcing effects of Al2O3-ZrO2 dispersion ceramics will be increased using NP with an intraparticle dispersion of these phases. Future applications of the LAVA prepared NP include biological fluorescence labeling, and drug targeting, magnetic resonance imaging, and hyperthermic cancer therapy, as well as sintering of load bearing ceramic implants, respectively.