Biocompatible and stable magnetosome minerals coated with poly-l-lysine, citric acid, oleic acid, and carboxy-methyl-dextran for application in the magnetic hyperthermia treatment of tumors

Abstract

Magnetic hyperthermia in which magnetic nanoparticles are introduced into tumors and exposed to an alternating magnetic field, appears to be promising.

A Method for Producing Highly Pure Magnetosomes in Large Quantity for Medical Applications Using Magnetospirillum gryphiswaldense MSR-1 Magnetotactic Bacteria Amplified in Minimal Growth Media

“…In addition to magnetosome spatial organization, we measured magnetosome number (n) and diameter (D) per/in bacterium at different time points (0, 1, 3, 20, 23, 26, 44, 47, and 50 h) during the 50 h of bacterial growth (Figures S1A,B). These two parameters increased from n = 2.5 ± 2.4 and D = 15.8 ± 4.5 nm at 0 h to n = 28.3 ± 7.8 and D = 33.5 ± 6.2 nm at 50 h, reaching a slightly larger value of n and smaller value of D compared with n ∼ 20 and D ∼ 42 nm determined for magnetotactic bacteria grown under environmental conditions (Schleifer et al, 1991;Scheffel et al, 2008;Lohße et al, 2016) or using the same methods/media as those of Zhang et al (Le Fèvre et al, 2017;Mandawala et al, 2017) with D = 37.6 ± 8.8 nm and n = 22.8 ± 8.1 after 50 h of cultivation.…”

“…Using these bacteria, it has been possible to produce nanoparticles that fulfill most of the criteria mentioned above (Alphandéry, 2014). In particular, MSR-1 magnetites display an organization in chains that prevents their aggregation (Heyen and Schüler, 2003), have high crystallinity, homogenous size distribution and improved heating properties in comparison to chemically synthesized IONP Mandawala et al, 2017). Hence, these biological nanoparticles have been considered for various medical applications, especially for tumor nanoparticle-mediated hyperthermia treatments (Alphandéry et al, 2017;Le Fèvre et al, 2017).…”

Natural Metallic Nanoparticles for Application in Nano-Oncology

“…a laser or an alternating magnetic field, heat appears to be the dominant mechanism of action since tumor disappearance is not observed in the absence of heat, and magnetosomes are therefore classifiable as medical devices. [54,85], (ii) a mechanism of tumor cell death dominated by apoptosis as was observed during in vitro studies where magnetosomes were brought into contact with GBM cells and then exposed to one magnetic session [53,84], (iii) anti-tumor activity due to the presence of the magnetosomes within tumor margin, (iv) the attraction of certain immune cells, such as PNN, in the region where magnetosomes are located, even so a direct link between the anti-tumor activity and the presence of PNN has not yet been established [53,84]. Table 2 summarizes the in vitro and in vivo anti-tumor efficacies obtained with the various types of nanoparticles presented in table 1.…”

“…Figure 4 illustrates, through a series of fours schematic diagrams, the different mechanisms that could be involved in the anti-tumor activity, i.e.,: (i) localized heat induced at magnetosome location that could occur inside or outside tumor cells, depending on whether (or not) magnetosomes have internalized in tumor cells [ 54 , 85 ], (ii) a mechanism of tumor cell death dominated by apoptosis as was observed during in vitro studies where magnetosomes were brought into contact with GBM cells and then exposed to one magnetic session [ 53 , 84 ], (iii) anti-tumor activity due to the presence of the magnetosomes within tumor margin, (iv) the attraction of certain immune cells, such as PNN, in the region where magnetosomes are located, even so a direct link between the anti-tumor activity and the presence of PNN has not yet been established [ 53 , 84 ]. In cases where magnetosomes are heated under the application of radiation, e.g.…”

Improved methods for mass production of magnetosomes and applications: a review

“…Since magnetosome formation results from the invagination of the bacterial membrane, the endotoxin concentration at the magnetosome surface might be higher than the tolerated concentration. Therefore, followed by the extraction and purification of magnetosomes from magnetotactic bacteria, organic materials such as endotoxins can be removed with the treatment of different detergents (SDS, Triton X100, phenol and chloroform) at 60°C in the presence of sonication [39]. The obtained uncoated magnetosome minerals can be characterized by transmission electron microscope (TEM).…”