Background:
Magnetic cell immobilization has been introduced as a novel, facile and
highly efficient approach for cell separation. A stable attachment between bacterial cell wall with
superparamagnetic iron oxide nanoparticles (SPIONs) would enable the microorganisms to be affected
by an outer magnetic field. At high concentrations, SPIONs produce reactive oxygen species
in cytoplasm, which induce apoptosis or necrosis in microorganisms. Choosing a proper surface
coating could cover the defects and increase the efficiency.
Methods:
In this study, asparagine, APTES, lipo-amino acid and PEG surface modified SPIONs
was synthesized by co-precipitation method and characterized by FTIR, TEM, VSM, XRD, DLS
techniques. Then, their protective effects against four Gram-positive and Gram-negative bacterial
strains including Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas
aeruginosa were examined through microdilution broth and compared to naked SPION.
Results:
The evaluation of characterization results showed that functionalization of magnetic nanoparticles
could change their MS value, size and surface charges. Also, the microbial analysis revealed
that lipo-amino acid coated magnetic nanoparticles has the least adverse effect on microbial
strain among tested SPIONs.
Conclusion:
This study showed lipo-amino acid could be considered as the most protective and
even promotive surface coating, which is explained by its optimizing effect on cell penetration and
negligible reductive effects on magnetic properties of SPIONs. lipo-amino acid coated magnetic
nanoparticles could be used in microbial biotechnology and industrial microbiology.
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