Detection of Microorganisms Using Artificial Siderophore-Fe Complex-Modified Substrates.

Four Fe complexes of typical artificial siderophore ligands containing catecholate and/or hydroxamate groups of tricatecholate, biscatecholate-monohydroxamate, monocatecholate-bishydroxamate, and trihydroxamate type artificial siderophores (K[], K[], K[], and []) were modified on Au substrate surfaces. Their abilities to adsorb microorganisms were investigated using scanning electron microscopy, quartz crystal microbalance, and AC impedance methods. The artificial siderophore-iron complexes modified on Au substrates (/Au, /Au, /Au, and /Au) showed the selective immobilization behavior for various microorganisms, depending on the structural features of the artificial siderophores (the number of catecholate and hydroxamate arms). Their specificities corresponded well with the structural characteristics of natural siderophores released by microorganisms and used for Fe ion uptake. These findings suggest that they were generated via specific interactions between the artificial siderophore-Fe complexes and the receptors on microorganism surfaces. Our observations revealed that the /Au systems may be potentially used as effective microbe-capturing probes that can enable rapid and simple detection and identification of various microorganisms.