High-Sensitivity Detection of Iron(III) by Dopamine-Modified Funnel-Shaped Nanochannels.

Iron as an essential trace element in the human body participates in various biological processes. The demand for efficient and sensitive detection of FeIII has drawn wide attentions. Inspired by biological nanochannels, a high-sensitivity, economic, and recyclable FeIII detection method is proposed by using dopamine (DOPA)-modified funnel-shaped nanochannels. Along with the FeIII concentration changing, different FeIII-DOPA chelates are generated in the channel, which affect the wettability and charge distribution of the pore surface, resulting in a change of ionic current through the nanochannels. Meanwhile, the funnel-shaped nanochannel applied in this work with a narrow cylindrical segment (a diameter close to 10 nm) as the critical section can enhance the sensing ability to the ultra-trace level (down to 10-12 M). We expound the mechanism and feasibility of this method and anticipate that the system can be a good example to design highly sensitive and stable ion detection devices.