Artificial Magnetic Bacteria: Living Magnets at Room Temperature

Abstract

Biogenic magnetite is a fascinating example of how nature can generate functional magnetic nanostructures. Inspired by the magnetic bacteria, an attempt is made to mimic their magnetic properties, rather than their structures, to create living magnets at room temperature. The non‐magnetic probiotic bacteria Lactobacillus fermentum and Bifidobacteria breve are used as bioplatforms to densely arrange superparamagnetic nanoparticles on their external surfaces, thus obtaining the artificial magnetic bacteria. Magnetic probiotic bacteria can be produced by using superparamagnetic maghemite nanoparticles assembled at their surfaces. They present a collective ferromagnetic phase at room temperature. The blocking temperature of these maghemite nanoparticles increases more than 100 K when assembled at the artificial magnetic bacteria.

Bioinspired Magneto-optical Bacteria

“…It must be emphasized that isolated iron oxide (magnetite or maghemite) nanoparticles of this size range (10 nm) are superparamagnetic at room temperature and do not show persistent magnetization. , However, once they are incorporated into the external bacterial surface, dipole–dipole interactions occur due to the close mutual proximity of the iron oxide particles so that the maghemite-gold bacteria behave as ferromagnets at room temperature. This behavior is consistent with results that we have reported previously, in which massive incorporation of iron oxide nanoparticles onto the bacteria surface yielded increased magnetic properties …”

Magnetic and Golden Yogurts. Food as a Potential Nanomedicine Carrier

“…TEM images (Figure 1a,b) show MNPs adhered to the entire surface of both strains of bacteria, and these hybrids appeared very similar to systems obtained previously with other probiotics [15]. MNPs adhere to bacterial EPS to produce the MNPs-ferment.…”

Magneto-optical hyperthermia agents based on probiotic bacteria loaded with magnetic and gold nanoparticles

“…MNP-bacteria characterization was carried out by TEM as reported previously. 34 The stability of this type of system in conditions similar to those of the stomach was verified in the past and the results were patented. 28…”