Nanopore detection of copper ions using a polyhistidine probe

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Biophysics

Background:

• Nanopore sensing offers high sensitivity for detecting analytes.
• Metal ion detection is crucial in environmental monitoring and biological studies.
• Developing selective and sensitive methods for copper ion detection remains a challenge.

Purpose of the Study:

• To develop a stochastic nanopore sensing method for sensitive and selective detection of copper ions (Cu2+).
• To utilize a polyhistidine molecule as a chelating agent for copper ions within a nanopore system.
• To establish the detection limit and assess the selectivity of the developed sensor against other metal ions.

Main Methods:

• Employed a stochastic nanopore sensing setup using an alpha-hemolysin pore.
• Utilized a polyhistidine molecule as a chelating agent to interact with Cu2+ ions.
• Analyzed translocation events of the chelating agent through the nanopore in the presence and absence of Cu2+.
• Differentiated Cu2+ signals from other metal ions (Co2+, Ni2+, Zn2+) based on event signatures.

Main Results:

• Achieved a detection limit of 40 nM for Cu2+ ions.
• Demonstrated high selectivity for Cu2+ detection, with minimal interference from Co2+, Ni2+, and Zn2+.
• Observed distinct event residence times and blockage amplitudes for copper-chelates compared to other metal chelates.

Conclusions:

• The developed stochastic nanopore sensing method is effective for trace amount detection of Cu2+.
• The polyhistidine chelating agent provides selectivity, enabling accurate Cu2+ quantification.
• This approach shows potential for broader application in developing nanopore sensors for various metal ions.