Polystyrene particles reveal pore substructure as they translocate

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Materials Science

Background:

• Resistive-pulse sensing is a technique used for particle analysis.
• Track-etched pores are commonly used in sensing applications.
• Understanding pore characteristics is crucial for improving sensing performance.

Purpose of the Study:

• To investigate the impact of pore geometry on resistive-pulse sensing.
• To explore the potential for simultaneous multi-particle detection.
• To analyze factors influencing particle translocation dynamics.

Main Methods:

• Experiments using cylindrical track-etched polyethylene terephthalate (PET) pores.
• Resistive-pulse sensing to monitor polymer spheres passing through pores.
• Analysis of pulse patterns to correlate with pore diameter variations.

Main Results:

• Pore diameters were found to fluctuate along their length, creating repeatable resistive pulse patterns.
• These patterns allow for unambiguous simultaneous resolution of multiple particles.
• Particle sticking and complete translocation can be accurately detected.
• Nonionic surfactant significantly reduces particle velocity, and particle size and charge can be differentiated.
• Electrophoresis, electroosmosis, and pore size influence particle motion.

Conclusions:

• Pore diameter fluctuations are a key feature influencing resistive-pulse sensing.
• The observed patterns enable advanced particle detection and analysis capabilities.
• These findings are vital for enhancing sensing speed, optimizing analyte detection, and characterizing particle shapes.