The micro-volume liquid focusing effect in Janus membrane and its biosensing application

Area of Science:

• Materials Science
• Analytical Chemistry
• Biotechnology

Background:

• Micro-volume analysis and specific detection are crucial for chemical sensing and biological testing.
• Traditional membrane filtration faces challenges with lateral diffusion, hindering micro-volume liquid transport.
• Improving selectivity and accuracy in detection requires effective membrane prefiltration techniques.

Purpose of the Study:

• To investigate focused transmembrane transport of micro-volume liquid using porous membranes with asymmetric (Janus) surface wettability.
• To develop and characterize a Janus membrane for improved microfluidic detection.
• To demonstrate the application of the Janus membrane in micro-volume liquid biosensing.

Main Methods:

• Fabrication of Janus membranes with hydrophilic (polydopamine) and hydrophobic (fluoropolymer) layers using dip-coating and roller-assisted liquid printing.
• Experimental verification of micro-volume liquid focusing effect using visual wetting circles and fluorescent tracers.
• Integration of the Janus membrane with a glucose test strip for biosensing applications.

Main Results:

• The Janus membrane demonstrated a significant micro-volume liquid focusing effect.
• Integration with a glucose test strip resulted in a 7.5x improvement in detected signal amplitude.
• The response time was improved 2.7x compared to conventional porous membranes.
• The study verified the dynamics of liquid transport through the Janus membrane.

Conclusions:

• The developed Janus membrane offers a novel strategy for microfluidic detection applications.
• This approach effectively balances detection volume, time, and selectivity through the micro-volume liquid focusing effect.
• The Janus membrane technology provides a new pathway for advancing chemical sensing and biological testing.