Artificial Siderophore-Modified Au electrode for Adsorption and Sensing Microbe

Abstract

The hydroxamate-typed artificial siderophores, tris [2-{3-(N-acyl-N-hydroxamino)propylamido}propyl]aminomethane (L1-L3, acyl-R group = Me, Et, and Ph, respectively) were prepared and their Fe III complexes, Fe III (L1-L3) (1-3) were modified on Au electrode surfaces. Complex 1-3 indicated biological activity for Microbacterium flavescens, which is hydroxamate-typed siderophore auxotrophic gram-positive microorganism, suggesting that these complexes were able to permeate the cell membrane of microorganism. The growth curve indicated the permeation ability of 1-3 depended on their terminal acyl groups. The modification of these complexes was carried out by stepwise self-assembling method. The cyclic voltammetry of the resultant Au electrodes, 1-3/Au confirmed the surface modification of 1-3. The adsorption experiments of M. flavescens with 1-3/Au were clearly showed that 1-3/Au could immobilize microorganisms. The images of the adsorption of M. flavescens were obtained by various microscopic methods. Quartz crystal microbalance (QCM) measurements also suggested that 1-3/Au was able to adsorb M. flavescens. The adsorption ability of 1-3/Au for microorganisms depended on the terminal bulky acyl group. The adsorption ability is due to the interaction between 1-3 on Au electrodes and receptor/binding protein in the cell membrane.