Ultrasensitive and Selective Copper(II) Detection: Introducing a Bioinspired and Robust Sensor
Lena K. Müller, Ivana Duznovic, Daniel Tietze, Wadim Weber, Mubarak Ali, Viktor Stein, Wolfgang Ensinger, Alesia A. Tietze
Abstract
Abstract A nanopore‐based Cu II ‐sensing system is reported that allows for an ultrasensitive and selective detection of Cu II with the possibility for a broad range of applications, for example in medical diagnostics. A fluorescent ATCUN‐like peptide 5/6‐FAM‐Dap‐β‐Ala‐His is employed to selectively bind Cu II ions in the presence of Ni II and Zn II and was crafted into ion track‐etched nanopores. Upon Cu II binding the fluorescence of the peptide sensor is quenched, permitting the detection of Cu II in solution. The ion transport characteristics of peptide‐modified nanopore are shown to be extremely sensitive and selective towards Cu II allowing to sense femtomolar Cu II concentrations in human urine mimics. Washing with EDTA fully restores the Cu II ‐binding properties of the sensor, enabling multiple repetitive measurements. The robustness of the system clearly has the potential to be further developed into an easy‐to‐use, lab‐on‐chip Cu II ‐sensing device, which will be of great importance for bedside diagnosis and monitor of Cu II levels in patients with copper‐dysfunctional homeostasis.