Graphene-Enabled High-Performance Electrokinetic Focusing and Sensing

Area of Science:

• Electrokinetic phenomena
• Microfluidics
• Materials science

Background:

• Transverse isoelectric focusing is ideal for micro total analysis.
• A key challenge is the lack of integrable electrode systems for reliable transverse isoelectric focusing and electrokinetic sensing in microfluidic devices.

Purpose of the Study:

• To develop microelectrodes for reliable transverse isoelectric focusing and electrokinetic sensing in microfluidic devices.
• To enhance protein separation and label-free detection sensitivity in microfluidic systems.

Main Methods:

• Development of microfluidic devices incorporating monolayer graphene microelectrodes.
• Electrolysis stability testing of graphene vs. inert-metal microelectrodes.
• Implementation of transverse isoelectric focusing and a three-dimensional multistream microfluidic strategy for label-free detection.

Main Results:

• Graphene microelectrodes exhibit >10^3 times improved electrolysis stability compared to inert-metal electrodes.
• Specific proteins were separated and concentrated to ~100 μm within minutes using transverse isoelectric focusing.
• Label-free protein detection sensitivity was enhanced ~10^2 times compared to state-of-the-art sensors.

Conclusions:

• Monolayer graphene microelectrodes overcome critical limitations in microfluidic electrokinetic analysis.
• The developed system allows for high-performance, efficient, and sensitive lab-on-a-chip protein analysis.
• This work paves the way for advanced microfluidic devices with maximal time and size efficiencies.