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

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 different concentrations, trying to get the best from each of them. We study which mixture performs better from different 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.

Nanoformulation Design Including MamC-Mediated Biomimetic Nanoparticles Allows the Simultaneous Application of Targeted Drug Delivery and Magnetic Hyperthermia

“…The effect of hyperthermia on the DOXO release from the nanoformulation that yielded better hyperthermia results was evaluated as described by Peigneux et al [ 22 ]. Briefly, an alternating magnetic field (frequency = 130 kHz, H = 20 kA/m) was applied to the suspension of the 25 TBM + 75 M nanoassemblies prepared at pH 7.4 and 5.0, and DOXO release was measured at different time points up to 75 min.…”

“…The presence of MamC attached to the surface of the BM provides functional groups to the nanoparticle without the need of additional coating and, also shifts the isoelectric point from ~7 for M to 4.4 for the BM [ 20 ]. This is crucial in making these BM optimal drug nanocarriers for two reasons: (1) at physiological pH values, BM are able to bind positively charged molecules through electrostatic interactions, which are weakened at acidic pHs (such as those found in tumor microenvironments), allowing the release of the adsorbed molecules [ 20 , 21 ]; (2) thanks to these electrostatic interactions, it is possible to attach to them not only the chemotherapy drug, but also to an active targeting agent, like a monoclonal antibody (mAb), as demonstrated previously by Peigneux et al [ 22 ]. However, although these BM are optimal drug nanocarriers, they do not display as strong a magnetic hyperthermia response as that exhibited by M [ 23 ].…”

Biomimetic Magnetoliposomes as Oxaliplatin Nanocarriers: In Vitro Study for Potential Application in Colon Cancer

“…However, these MmsF-mediated magnetic nanoparticles are still not characterized enough to determine whether or not they could be of use in nanotechnology. On the contrary, MamC-mediated biomimetic nanoparticles (here referred as BMNPs) have demonstrated their potential as promising drug nanocarriers [5,6,14,15] and as hyperthermia agents [16,17], opening the possibility of a combined therapy by using the same nanoplatform. MamC controls magnetite nucleation and growth by both template and ionotropic effects [18], remaining attached to the nanoparticles and forming a nanocomposite (95 wt% magnetite + 5 wt% MamC) that results, not only in magnetic nanoparticles of different size and morphology (and thus magnetic properties) compared to those of chemically produced ones, but also in nanoparticles with novel surface properties [5].…”

In vitro hyperthermic effect of magnetic fluid on cervical and breast cancer cells

“…The MFH based therapy includes administration of biocompatible magnetic fluid (MF) directly into the tumor which is placed under an alternating magnetic field with a frequency between 100 and 500 kHz. The magnetic nanoparticles (MNPs) sense the magnetic field and generate localized heating under the AC magnetic field via mechanisms of hysteresis and relaxation losses 5 – 7 . The aim of the MFH therapy is to achieve the hyperthermia temperature between 43 and 45 °C in minimum possible time and maintain it for a sufficient duration for the successful killing of cancer cells without affecting the surrounded healthy tissues.…”