On-chip microdialysis system with flow-through glucose sensing capabilities.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Materials Science

Background:

• Microdialysis enables continuous metabolite monitoring with minimal disruption.
• Existing microdialysis systems for diabetes treatment suffer from large dead volumes, limiting sensing frequency.
• An integrated miniaturized microdialysis probe and glucose sensor could overcome these limitations.

Purpose of the Study:

• To develop and evaluate an in situ integrated microdialysis probe with an electrochemical glucose sensor.
• To address the limitations of dead volume and sensing frequency in current diabetes monitoring systems.

Main Methods:

• Fabrication involved bonding a polycarbonate track-etch membrane (100-nm pores) onto microfluidic channels.
• Electrochemical glucose sensing electrodes were patterned within the microfluidic channels.
• In vitro experiments were conducted to assess glucose permeability, recovery, and lag time.

Main Results:

• Achieved a glucose permeability of 5.44 mum/s through the 100-nm pore polycarbonate membrane.
• Demonstrated 99% glucose recovery at a perfusion flow rate of 0.5 microl/min.
• Measured a total lag time of 210 seconds, with 45 seconds due to mass transfer limitations.

Conclusions:

• The integrated system continuously tracks glucose concentration changes with high sensitivity.
• The system shows potential for physiologically relevant glucose monitoring in diabetes treatment.
• Expected lag time is under 1 minute with minimal amplitude reduction for improved continuous glucose monitoring.