Relevant Parameters for Magnetic Hyperthermia in Biological Applications: Agglomeration, Concentration, and Viscosity

Magnetic hyperthermia (MH) applications based on superparamagnetic nanoparticles are behind many theragnostic developments, some of which are entering into a stage of commercial maturity (see Magforce). Theoretical frames, such as the well-established Rosensweig formulation, rely on studies performed on ideal ferrofluids in which viscosity, concentration, or pH are homogeneous throughout the sample. However, biological environments are deeply complex, dynamic, and heterogeneous, making the nanobiointeraction the leading variable controlling the MH performance. Biological MH applications depend on a larger set of parameters than those currently studied: agglomeration, type of coating, viscosity, and local concentration are marginally studied and produce intricate and nonlinear responses in biological MH applications.