Electron Transfer Mediated by Surface-Tethered Redox Groups in Nanofluidic Devices

Area of Science:

• Electrochemistry
• Nanofluidics
• Polymer Science

Background:

• Electrochemistry offers potent transduction and amplification for integrated assays.
• Nanofluidic devices with microelectrodes enable precise control over molecular interactions.

Purpose of the Study:

• To demonstrate cyclic voltammetric detection of flexible polymers functionalized with redox-active ferrocene moieties.
• To explore the relationship between polymer length and amplified electrical current in a nanofluidic sensor.

Main Methods:

• Surface-tethering of ferrocene-functionalized poly(ethylene glycol) polymers within a nanofluidic device.
• Utilizing cyclic voltammetry to measure electron shuttling between microelectrodes separated by <100 nm.
• Analyzing the steady-state electrical current generated by polymer diffusion and redox group activity.

Main Results:

• Achieved greatly amplified steady-state electrical current through electron shuttling facilitated by polymer diffusion.
• Demonstrated that polymer length directly influences the measured current, indicating control over sensor output.
• Observed that Fc moiety activity correlates with the interpenetration of polymer layers on opposing electrodes.

Conclusions:

• Nanofluidic enabled electrochemical sensors provide an amplified and highly sensitive detection alternative.
• Design principles for sensors based on polymer length, flexibility, and analyte binding are outlined.
• This platform enables the development of novel biosensing devices with tunable sensitivity.