Size-Dependent Assessment of Fe3O4-Nanoparticles Loaded into Porous Silicon

Abstract

Iron oxide nanoparticles of different sizes (8, 5 and 3.8 nm) have been infiltrated into the pores of porous silicon matrices, offering a hybrid system with tunable magnetic properties due to the morphology of the matrix, the loading of the nanoparticles and their size. For biomedical applications a superparamagnetic behaviour at room temperature is required, which has been verified for the three particle sizes investigated here. Temperature dependent magnetization measurements show that the blocking temperature is far below room temperature for all three composite systems. Furthermore the toxicity of these composite samples with regard to cell-viability has been investigated. A trypan blue-based dye exclusion test has been used to determine the number of viable cells present in suspensions of HEK 293 cells and resulted in a minimum viability above 90% (by the 5th day) in the case of all three particle sizes infiltrated into the porous Si matrix.