Because of the serious neurologic consequences of iron deficiency and iron excess in the brain, interest in the iron status of the central nervous system has increased significantly in the past decade. While iron plays an important role in many physiological processes, its accumulation may lead to diseases such as Huntington's, Parkinson's, and Alzheimer's. Therefore, it is important to develop methodologies that can monitor the presence of iron in a selective and sensitive manner. In this paper, we first showed the synthesis and characterization of the iron-binding protein (FBP) from Haemophilus influenzae, specific for ferrous ions. Subsequently, we employed this protein in our nanopipette platform and utilized it in functionalized nanoprobes to monitor the presence of ferrous ions. A suite of characterization techniques: absorbance spectroscopy, dynamic light scattering, and small-angle X-ray scattering were used for FBP. The functionalized Fe-nanoprobe calibrated in ferrous chloride enabled detection from 0.05 to 10 μM, and the specificity of the modified iron probe was evaluated by using various metal ion solutions.
Keywords: Haemophilus influenzae; iron; iron characterization; nanopipette; sensing.