Production of iron nanoparticles using e. coli for mri contrast agent

Abstract

Ferritins are known to be essential iron storage and detoxification proteins found in organisms. Ferritin found in archaeon Archaeoglobus fulgidus (AfFtn), has a distinct structure compared to normal ferritin, due to the presence of four large pores of 45 Å in diameter each. These proteins are fully assembled into 24-mers structures only at high salt concentrations or in the presence of iron. The ability of AfFtn to sequester iron from its environment and form nanocores may readily produce nanoparticles for possible applications as MRI contrast agent. The project aimed to investigate the amount of iron absorbed by Escherichia coli cells, transformed with Archaeoglobus fulgidus ferritin(AfFtn) gene and cultured at different iron concentrations. MRI scans of iron-loaded AfFtn were conducted to determine the relaxivity parameters of the iron-loaded ferritin. The amount of iron sequestered by the E. coli within the ferritin was quantified. Iron colourimetric analysis suggested that in environments of higher iron concentrations, greater amounts of iron were absorbed by AfFtn. Iron per 24-mer ratios also exhibited a significant in Escherichia coli cells cultured at increasing iron concentrations. MRI analysis of iron-containing AfFtn showed higher T2* values, as compared to T1 values. However, when compared to gadovist, which is a positive contrast agent, the T1 relaxivity of iron-loaded AfFtn is 4 times small than that of gadovist, and 2 times smaller in T2 relaxivity than that of gadovist. More work has to be conducted to improve on its suitability as a MRI contrast agent.