Biocompatible Iron-Boron Nanoparticles Designed for Neutron Capture Therapy Guided by Magnetic Resonance Imaging.

The combination of multiple functions in a single nanoparticle (NP) represents a key advantage of nanomedicine compared to traditional medical approaches. This is well represented by radiotherapy in which the dose of ionizing radiation should be calibrated on sensitizers biodistribution. Ideally, this is possible when the drug acts both as radiation enhancer and imaging contrast agent. Here, an easy, one-step, laser-assisted synthetic procedure is used to generate iron-boron (Fe-B) NPs featuring the set of functions required to assist neutron capture therapy (NCT) with magnetic resonance imaging. The Fe-B NPs exceed by three orders of magnitude the payload of boron isotopes contained in clinical sensitizers. The Fe-B NPs have magnetic properties of interest also for magnetophoretic accumulation in tissues and magnetic hyperthermia to assist drug permeation in tissues. Besides, Fe-B NPs are biocompatible and undergo slow degradation in the lysosomal environment that facilitates in vivo clearance through the liver-spleen-kidneys pathway. Overall, the Fe-B NPs represent a new promising tool for future exploitation in magnetic resonance imaging-guided boron NCT at higher levels of efficacy and tolerability.

Multitherapy magnetic theranostic: Synthesis, characterization and in vitro evaluation of their performance.

It is well known that iron oxide magnetic nanoparticles (IONPs) have many potential utilities in biomedicine due to their unique physicochemical properties. With the aim to obtain multifunctional nanoparticles with potential uses for therapy and diagnosis (nanotheranostics), IONPs were synthesized by hydrothermal synthesis assisted by mannose. Two synthetic pathways were evaluated in order to obtain IONPs with suitable properties for biomedical applications. The formulation Mag@Man/H1 presented the best characteristics in terms of size and stability. Mag@Man/H1 was evaluated as: a) drug carrier, b) antioxidant activity, c) magnetic hyperthermia, d) contrast agent for MRI. To evaluate the point a), morin, a natural flavonoid with several pharmaceutical activities, was loaded on the nanoparticles. A high percentage of drug loading was achieved. In point b) it was determined that the carrier itself possess a high activity which increased in morin loaded nanoparticles. Point c) magnetocalorimetric evaluation were carried out at several field conditions. A specific absorption rate value of 121.4 W/gFe was achieved at 52.4 kA/m and 260 kHz and 8.8 W/gFe at 4 kA/m and 100 kHz. Regarding contrast capacity (point d), the r1 value found was close to some contrast agent based on manganese. Although the measured r2 value was quite smaller than other iron oxides, the achieved effect was strong enough to produce negative contrast. From these studies, it was concluded that Mag@Man/H1 could act as a multifunctional nanoplatform for oncological diseases treatments.