Adsorption and detection of Escherichia coli using an Au substrate modified with a catecholate-type artificial siderophore-Fe3+ complex

作者：Inomata Tomohiko^*; Tanabashi Hirohito; Funahashi Yasuhiro; Ozawa Tomohiro; Masuda Hideki

来源：Dalton Transactions, 2013, 42(45): 16043-16048.

DOI：10.1039/c3dt51448j

A catecholate-type artificial siderophore with a terminal-NH2 group (1) and its Fe3+ complex (2) were prepared. Siderophore 1 was characterized by 1H NMR, FT-IR, and ESI-TOF MS spectroscopy. The corresponding Fe3+ complex 2 was obtained by reaction of 1 with Fe(acac)(3). The absorption band at 500 nm (epsilon = 4670 M-1 cm(-1) at pH 7.0) of the electronic absorption spectrum of 2 is assignable as the LMCT (Ocatecholate -%26gt; Fe3+) absorption band. This band indicates the formation of the Fe3+ complex of 1. The biological activity of 2 with respect to Escherichia coli was clearly confirmed by observing that it permeates into the cell membrane. The self-assembled monolayer of 2 on an Au substrate, 2/Au, was prepared and its preparation was confirmed by FT-IR reflection-absorption spectroscopy (IR-RAS) and cyclic voltammetry (CV). Furthermore, a quartz crystal microbalance (QCM) chip modified with 2 effectively adsorbed E. coli. M. flavescens, an organism which is incapable of synthesizing siderophores and must therefore use exogenous hydroxamate-type siderophores for growth, did not adsorb on 2/Au. In contrast, E. coli did not adsorb on the hydroxamate-type artificial siderophore-Fe3+ complex (3)-modified Au substrate, 3/Au. These results provide preliminary evidence that microbes recognized Fe3+ ion-bound siderophores on the surface. The detection limit of 2/Au was similar to 10(4) CFU mL(-1).

• 出版日期2013