Resistive Pulse Sensing on a Capillary-Assisted Microfluidic Platform for On-Site Single-Particle Analyses.

Area of Science:

• Microfluidics
• Electrical Sensing
• Surface Chemistry

Background:

• Capillary-assisted flow simplifies microfluidic systems for on-site applications.
• Microfluidic platforms require stable, easily modifiable designs for consistent performance.
• Resistive pulse sensing (RPS) is a label-free method for detecting single analytes.

Purpose of the Study:

• To develop a stable capillary-assisted microfluidic platform for on-site electrical sensing.
• To investigate a one-step surface modification for enhanced microfluidic flow.
• To demonstrate the platform's utility in label-free detection and size analysis.

Main Methods:

• One-step modification of polydimethylsiloxane (PDMS) with polyethylene glycol (PEG).
• Utilizing PEG-PDMS surfaces for capillary-assisted electrolyte flow in microfluidic chips.
• Employing resistive pulse sensing (RPS) for detecting micrometer particles and bacterial cells.

Main Results:

• PEG-PDMS surfaces maintained hydrophilicity and capillary flow after 30 days of ambient storage.
• Successful label-free detection and size analysis of micrometer particles and bacterial cells were achieved.
• The microfluidic chip demonstrated stability and reliable performance after dry storage.

Conclusions:

• The developed capillary-assisted microfluidic platform offers a stable and simple solution for on-site electrical sensing.
• The PEG modification ensures long-term functionality, enabling portable pathogen detection.
• This technology facilitates on-site, label-free analysis of single analytes, including pathogens.