Previous studies conducted by our research group at room temperature and pressure and neutral pH with the bacteria Shewanella oneidensis, a ferruginous smectite, and M1 minimal nutrient media resulted in the formation of numerous nanoparticulate secondary precipitates. A few of the nanoparticulate solid phases that were observed include Fe-rich grains and amorphous Si globules in the immediate vicinity of bacterial cells and extracellular polymeric substances. In reducing systems, siderite was also found. Further study of the Si precipitates revealed that polyamine, a biomolecule, was polymerizing and stabilizing the Si nanoprecipitates under conditions in which one would not expect Si precipitation. Despite these types of observations in biological systems, most synthesis methods for siderite (FeCO₃) and Fe-oxides involve high temperatures, high pressures, and/or extreme pH values. The objectives of this study are to synthesize and characterize Fe mineral nanoparticles under conditions which imitate nature (i.e., biomimetic conditions) and to begin to understand the role that biomolecules play in nanoparticle synthesis at low temperatures and pressures and relatively neutral pH values. Controlled studies will use biomolecules such as alginate (exopolysaccharide of Pseudomonas), dextran (a neutral polysaccharide), arganine (a polyamine used in M1 media), and albumin (a protein). Products will be examined under transmission electron microscopy and accompanying selected area electron diffractions, energy dispersive electron spectroscopy, and electron energy loss spectroscopy. Additionally, particle size and isoelectric points will be determined using a Malvern Zetasizer Nano ZS. Determination of the isoelectric point of the nanoparticles in suspension will allow us to determine the charge of the nanoparticles at various pH values and the stability of the nanoparticles in the measuring solution.