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 (ε = 4670 Mâ1 cmâ1 at pH 7.0) of the electronic absorption spectrum of 2 is assignable as the LMCT (Ocatecholate â 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 reflectionâabsorption 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 siderophoreâFe3+ 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 â¼104 CFU mLâ1.
制备了带有末端NH2基团的
儿茶酚盐型人工
铁载体(1)及其Fe3+络合物(2)。通过 1H NMR、FT-IR 和 ESI-TOF MS 光谱对
铁载体 1 进行了表征。 1与Fe(acac)3反应得到相应的Fe3+配合物2。 2 的电子吸收光谱在 500 nm 处的吸收带(pH 7.0 时,Δ = 4670 M−1 cm−1)可指定为 L
MCT(
儿茶酚酯−Fe3+)吸收带。该条带表明形成了1的Fe3+络合物。通过观察其渗透到细胞膜中,清楚地证实了2对于大肠杆菌的
生物活性。在Au基底上制备了2的自组装单层2/Au,并通过FT-IR反射吸收光谱(IR-RAS)和循环伏安法(CV)证实了其制备。此外,
石英晶体微天平(QCM)芯片经过2个修饰,可有效吸附大肠杆菌。 M. flavescens 是一种无法合成
铁载体并因此必须使用外源异羟
肟酸型
铁载体来生长的
生物体,它不吸附在 2/Au 上。相比之下,大肠杆菌不吸附异羟
肟酸型人工
铁载体-Fe3+复合物(3)-修饰的Au底物3/Au。这些结果提供了微
生物识别表面 Fe3+ 离子结合
铁载体的初步证据。 2/Au 的检测限为~104 CFU mL~1。