**Enhancement of Magnetic Hyperthermia by Mixing Synthetic Inorganic and Biomimetic Magnetic Nanoparticles**

**Guillermo R. Iglesias 1,\*, Ylenia Jabalera 2, Ana Peigneux 2, Blanca Luna Checa Fernández 1, Ánge<sup>l</sup> V. Delgado 1 and Concepcion Jimenez-Lopez 2,\***


Received: 30 March 2019; Accepted: 27 May 2019; Published: 11 June 2019

**Abstract:** In this work we report on the synthesis and characterization of magnetic nanoparticles of two distinct origins, one inorganic (MNPs) and the other biomimetic (BMNPs), the latter based on a process of bacterial synthesis. Each of these two kinds of particles has its own advantages when used separately with biomedical purposes. Thus, BMNPs present an isoelectric point below neutrality (around pH 4.4), while MNPs show a zero-zeta potential at pH 7, and appear to be excellent agents for magnetic hyperthermia. This means that the biomimetic particles are better suited to be loaded with drug molecules positively charged at neutral pH (notably, doxorubicin, for instance) and releasing it at the acidic tumor environment. In turn, MNPs may provide their transport capabilities under a magnetic field. In this study it is proposed to use a mixture of both kinds of particles at two di fferent concentrations, trying to ge<sup>t</sup> the best from each of them. We study which mixture performs better from di fferent points of view, like stability and magnetic hyperthermia response, while keeping suitable drug transport capabilities. This composite system is proposed as a close to ideal drug vehicle with added enhanced hyperthermia response.

**Keywords:** biomimetic magnetite; drug delivery; magnetic hyperthermia; magnetite; MamC; nanoparticles stability
