The adhesion of bacteria to surfaces is an important biological process, but one that has resisted simple categorization due to the number and complexity of parameters involved. The roughness of the substrate is known to play a significant role in the attachment process, particularly when the surface irregularities are comparable to the size of the bacteria and can provide shelter from unfavorable environmental factors. According to this scenario, roughness on a scale much smaller than the bacteria would not be expected to influence the initial attachment. To test this hypothesis, the impact of nanometer-scale roughness on bacterial attachment has been investigated using as-received and chemically etched glass surfaces. The surface modification by etching resulted in a 70% reduction in the nanoscale roughness of the glass surface with no significant alteration of its chemical composition or charge. Nevertheless, the number of bacteria adhering to the etched surface was observed to increase by a factor of three. The increase in attachment was also associated with an alteration in cellular metabolic activity as demonstrated by changes in characteristic cell morphologies and increased production of extracellular polymeric substances. The results indicate that bacteria may be more sensitive to nanoscale surface roughness than was previously believed.

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This research was focused on the possibility of iron sensing by means of bacterial cultures. The effect of ferric and ferrous ions on Pseudomonas aeruginosa, which has the ability to uptake the environmental iron in the form of complex iron compositions named siderophores, characterized by luminescent features, was studied. The different sensitivity to the iron from oxide compounds in comparison to the iron from chlorides and sulfate was emphasized by means of fluorescence measurements. It could be stated that Pseudomonas aeruginosa, from human body specimens could be the biological component of an iron biosensor for ferrofluid traces reminiscent after the administration for medical purposes.

Comparative study on the ferrophase dimensional distribution within a water ferrofluid was carried out by applying the atomic force microscopy (AFM) scanning and the transmission electron microscopy (TEM). The ferrophase has a magnetite core prepared by chemical co-precipitation and a double layer coating of citric acid. The diameter histograms revealed the main peak at about 9 nm which is concordant with a high degree of stability of the ferrofluid.

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