Chuanhua Duan

Rapid Detection of Ultra-Low concentration of Nanoparticles using trapping-based Nanopore Sensing and Free-Flow Electrophoresis

Project Description

Synthetic and natural nanoparticles, such as polymeric/metallic nanoparticles, quantum dots, liposomes, micelles, and bacteria, play critical roles in many industrial and biological processes. Rapid and quantitative analysis of these nanoparticles is thus of great importance. Nanopore sensors are one of the first class of ultra-sensitive label-free sensors for nanoparticle detection. Single particle sensitivity is generally achieved by detecting the transient decrease in ionic conductivity through the nanopore caused when a nanoparticle of interest translocates and thus partially blocks the nanopore. Quantitative analysis involves counting the transient conductivity events as nanoparticles pass sequentially through the pore. One major challenge that arise for quantitative analysis using nanopore sensors is their incapability of detecting low concertation solutions as the time interval between two translocation event, which is determined by the diffusion time of nanoparticle toward the nanopore, is reversely proportional to the particle concentration.

The goal of this project is to develop a new nanofluidic sensor for rapid detection of ultra-low concentration of nanoparticles. The NEFT lab has developed a new nanopore sensing strategy, i.e. trapping-based sensing strategy, to detect nanoparticles using nanopores. This sensing strategy utilizes a electrokinetic trapping phenomenon, where charge nanoparticles got trapped near the nanopore and thus gave a stable current/conductivity change. We plan to create a nanofluidic sensor with an array of nanopores that allow nanoparticle trapping. Students/teachers working in this project will use the new nanofluidic sensor to detect nanoparticle solutions with various concentrations. We also plan to implement free-flow electrophoresis, a common technique used to separate and focus nanoparticles in this sensor to pre-concentrate nanoparticles. Students/teachers working in this project will also investigate the effect of free-flow electrophoresis on rapid detection of nanoparticle solutions with ultra-low concentration.

Laboratory Mentors

Principal Investigator: Chuanhua Duan

Graduate Students: Rami Yazbeck, Yixin (Vera) Xu

Research Goals

– Detect various nanoparticle concentration using trapping-based nanopore sensing and nanopore array;
– Investigate the effect of free-flow electrophoresis on pre-concentration;
– Detect nanoparticle solutions with ultralow concentrations.

Learning Goals

– Gain basic understanding of electrokinetic trapping near nanopore;
– Learn how to conduct trapping-based nanopore sensing experiment;
– Learn how to use inverted microscope;
– Learn how to perform free flow electrophoresis;
– Leann how to achieve rapid detection of nanoparticles with ultra-low concentrations.

Learn more about Professor Duan on his faculty page.