Poly-L-lysine designed magnetic nanoparticles for combined hyperthermia, magnetic resonance imaging and cancer cell detection

The aim of this study was to test the suitability of poly-L-lysine coated magnetic nanoparticles for combined magnetic hyperthermia and magnetic resonance imaging (MRI) to unify the therapeutic and diagnostic approach. For this purpose, we have synthetized magnetic iron oxide (Fe3O4) nanoparticles of core diameter similar to 10 nm and modified with Poly-L-lysine (PLL) to stabilize the particles and improve their biocompatibility. These modified nanoparticles (MFPLL) were tested for magnetic hyperthermia suitability by calorimetric measurements. Based on the estimated heating rates the specific absorption rates (SAR) for MFPLL particles were calculated. The SAR values of MFPLL particles were about 14-15 Wg(-1) at frequency 190 kHz and applied field similar to 8 kAm(-1). In the MRI parametric mapping measurements we demonstrated the significant effect of MFPLL on transversal relaxation time T-2 with the relaxivity r(2) equal to 487.94 mM(-1) s(-1). The combination of the heating properties with the cytotoxic activities of MFPLL and MRI parameters holds great promise for the future development of targeted synergistic cancer treatment. Furthermore, as our previous results confirmed the cytotoxic activities of MFPLL in a cell type-dependent manner and the binding to cells expressing carbonic anhydrase (CA IX) when conjugated with the CA IX-specific antibody we have studied the antibody conjugated MFPLL nanoparticles in 3D spheroidal culture.