Solid and aqueous magnetoliposomes as nanocarriers for a new potential drug active against breast cancer

Abstract

Iron oxide nanoparticles, with diameters around 12nm, were synthesized by coprecipitation method. The magnetic properties indicate a superparamagnetic behavior with a coercive field of 9.7Oe and a blocking temperature of 118K. Both aqueous and solid magnetoliposomes containing magnetite nanoparticles have sizes below 150nm, suitable for biomedical applications. Interaction between both types of magnetoliposomes and models of biological membranes was proven. A new antitumor compound, a diarylurea derivative of thienopyridine, active against breast cancer, was incorporated in both aqueous and solid magnetoliposomes, being mainly located in the lipid membrane. A promising application of these magnetoliposomes in oncology is anticipated, allowing a combined therapeutic approach, using both chemotherapy and magnetic hyperthermia.

Magnetoliposomes containing magnesium ferrite nanoparticles as nanocarriers for the model drug curcumin

“…These systems exhibit diameters of 122 ± 19 nm (size distribution in electronic supplementary material, figure S2), with a low polydispersity (below 0.2). This result is similar to the one reported recently for AMLs of the same lipid containing iron oxide nanoparticles [ 36 ], however, being somewhat higher than those of AMLs containing transition metal ferrites [ 33 , 34 ]. For enhanced permeability and retention effect of loaded drugs, the size of magnetoliposomes must be small, and a successful extravasation into tumours has been shown to occur for nanocarriers with sizes below 200 nm [ 64 ].…”

“…Figure 7 shows the emission spectra of this dye in AMLs, SMLs and liposomes without magnetic nanoparticles (but with the same concentration of compound), which allow concluding that curcumin is fully incorporated in these nanosystems, as it is non-emissive in aqueous media. It is also possible to observe a quenching effect of the fluorophore emission by the magnetic nanoparticles, much more pronounced in SMLs, similar to what was reported for other potential drugs and different magnetic nanoparticles [ 34 – 36 ]. Also, a small red shift in emission is detected in liposomes and AMLs, when compared with SMLs, indicating a more hydrated environment for curcumin in the latter nanosystems, which was expected considering that SMLs do not contain an interior aqueous volume.…”

“…It was impossible to obtain good fits when considering a direct spinel structure of type Mg Td Fe 2 Oh O 4 as indicated in CIF 1011245. As the peaks (2 2 0) and (4 4 0) have increased intensities when compared with that of the main peak, (3 1 1), inclusion of preferential orientation correction at (1 1 0) plane [ 36 ] resulted in a small but insufficient improvement (electronic supplementary material, table S1). Considering that the spinel structure has a cation ordering according to Mg Td (1−i) Fe Td i Mg Oh i Fe Oh (2−i) O 4 , the Rietveld optimization resulted in a reasonable fit for a degree of inversion, i , of 0.897, with χ 2 = 2.92 and an R F factor of 6.8.…”

“…Curcumin was entrapped in AMLs by the co-injection method, while in solid magnetoliposomes the drug was incorporated by injection of an ethanolic solution together with the formation of the second lipid layer, as already reported for the incorporation in magnetoliposomes of several new anti-tumour compounds [ 34 – 36 ].…”

“…A single magnetoliposome is observed in figure 6 b . The size obtained is slightly smaller than those of SMLs of DPPC containing MnFe 2 O 4 and Fe 3 O 4 nanoparticles [ 35 , 36 ]. As reported previously [ 35 ], the interest in using a DPPC bilayer in SMLs is the melting transition temperature of this phospholipid ( T m = 41°C) [ 66 ], approaching the temperatures used in mild hyperthermia therapy.…”