Magnetic nanoparticles(MNPs)have widely been synthesized through chemical processes for biomedical applications over the past few decades.Recently,a new class of MNPs,known as bacterial magnetosomes,has been isolated from magnetotactic bacteria,a natural source.These magnetosomes are magnetite or greigite nanocrystals which are biomineralized in the bacterial cell and provide magnet-like properties to it.Contrary to MNPs,bacterial magnetosomes are biocompatible,lower in toxicity,and can be easily cleared from the body due to the presence of a phospholipid bilayer around them.They also do not demonstrate aggregation,which makes them highly advantageous.In this review,we have provided an in-depth comparative account of bacterial magnetosomes and chemically synthesized MNPs in terms of their synthesis,properties,and biomedical applications.In addition,we have also provided a contrast on how magnetosomes might have the potential to successfully substitute synthetic MNPs in therapeutic and imaging applications.