Basic Information

Abstract Number: 2600 - 3
Author Name: Zuzanna S Siwy - University of California Irvine
Session Title: Chemical Noise
Event Type: Symposia
Event Title: Diffusion and Trapping of Single Particles in Pores with Combined Pressure and Dynamic Voltage

Presider Name:Paul BohnCo-Author:Matthew Schiel
Affiliation:University of Notre DameAffiliation:University of California Irvine

Date: Thursday, March 12, 2015
Start Time: 02:10 PM (Slot #3)
Location: 242

Abstract Content

Single pores have been used as a basis for the detection of single molecules, viruses, particles and cells using the principle of the Coulter counter approach. Each object passing through a pore causes a transient change of the system resistance whose amplitude and duration give information on physical and sometimes even chemical properties of the object. The Coulter counter technique typically involves recording passage of many particles so that appropriate statistics of the translocation time and the pulse amplitude can be obtained. In case however of an unknown and potentially diluted mixture, a different approach might have to be taken. Instead of statistics on an ensemble of particles/molecules, statistics based on one particle studied many times is needed. In the presentation, we will discuss resistive-pulse experiments with polystyrene particles whose transport through pores is controlled by modulating the driving voltage during the process of translocation. Balancing all forces acting on single particles allowed us to observe random walk in a form of ion current fluctuations in time, and diffusion coefficient of individual particles was determined based on variance of their local diffusion velocities. The developed approach is applicable to particles of different sizes, does not require fluorescence labeling or tracking, and is entirely based on ion current recordings. Analysis of particles from mixture will be presented as well. The same technique was used to trap single particles in the pore for tunable time between tens of milliseconds to 40 seconds.