Magnetic and non Magnetic Characterization of Intracellular Biogenic Crystals Synthesized by Freshwater Magnetotactic Bacteria

摘要

Intracellular biogenic crystals synthesized by freshwater magnetotactic bacteria (MTBs) from La Fe Dam and Calima Lake - Colombia were separated from water/sediment samples using a magnetic field of 6 Gauss. Bacterial concentrates were observed by transmission electron microscopy (TEM) and analyzed with ray X microdiffraction (microXRD), Fourier transformed infrared spectroscopy (FTIR) and magnetic measurements. Magnetosomes were measured and analyzed with EDX/TEM (Energy dispersive X - ray analysis). Results showed magnetite crystals with cuboctahedral, hexagonal prismatic and bullet morphology; most crystals were classified in the single domain magnetic state, with an average length smaller than 100 nm. Samples with MTBs were saturated in a field close to 100 mT, showing ferrimagnetic behavior. These results open the path to others studies with MTBs in Colombia that could lead to find future applications for magnetic biominerals in nanobiotechnology and medicine.