Characterization of Protein Aggregation by Solid State Nanopore

Student: Mitu Acharjee

Degree: Ph.D., May 2021

Major Professor: Dr. Jiali Li

Research Area(s):

Nanoscale Materials & Devices

Biological Materials & Devices

Many neurodegenerative diseases like Alzheimer, Parkinson and Prion are found to be linked to protein aggregation. Existing protein characterization methods are:
- Not easily available.
- Expensive.
- Low precision rate.

Proteins translocate through a single nanopore in a Si3N4 membrane that separates two salt solution-filled chambers whose only connection was via the electrolyte (KCl) solution inside the nanopore.
Protein molecules translocating through a nanopore partially block the ion flow and the current blockage pulse or event can be measured.
By measuring the current and using nanopore geometry the translocated protein and its aggregations can be characterized.

Solid-state nanopore (6-30 nm) has been fabricated and imaged using TEM.
Tetrameric and hexameric aggregations of β-lactoglobulin protein were detected using 18 nm nanopore.
Dimeric aggregations of tau protein were detected using 10 nm nanopore as a function of salt concentration and pH.
The dimeric aggregations of α and β tubulins were detected in 1M KCl solution at 60 – 210 mV.
The pentameric to heptameric aggregations of tau and tubulin were detected in 1M KCl solution at 60 – 210 mV.

This work supports the understanding of the theory and principle of:
- Tau and tubulin aggregations in ionic solution using solid-state nanopore device.
- In vitro tau and tubulin aggregations manipulations using pH and salt concentration changing.
- In vitro protein aggregation reduction using applied voltage.

Study on the mechanisms of protein aggregations in live cells and pH, voltage, temperature and salt effects on the aggregation.