Single-particle electrophoresis in nanochannels

Area of Science:

• Nanotechnology
• Biophysics
• Virology

Background:

• Hepatitis B Virus (HBV) capsids are crucial for viral assembly and infection.
• Characterizing individual HBV capsid variants is essential for understanding viral dynamics.
• Nanofluidic devices offer precise control for analyzing nanoscale biological entities.

Purpose of the Study:

• To measure the electrophoretic mobilities and particle sizes of individual Hepatitis B Virus (HBV) capsids.
• To investigate capsid behavior in nanofluidic channels with precisely engineered nanopores.
• To determine the influence of electric field strength on capsid transport and resolution.

Main Methods:

• Utilized nanofluidic channels with serial nanopores fabricated using focused ion beam milling.
• Employed resistive-pulse sensing to detect and analyze individual HBV capsids transiting nanopores.
• Varied electric field strengths to study their effect on capsid mobility and signal resolution.

Main Results:

• Successfully resolved and discriminated between T=3 (32 nm) and T=4 (35 nm) HBV capsids based on their electrophoretic mobility and size.
• Observed that signal-to-noise ratio and capsid distribution resolution improved with increased electric field strength.
• Found that at high electric fields, T=3 and T=4 capsids exhibited identical electrophoretic mobilities, overcoming pore-induced hindrance.

Conclusions:

• Nanofluidic resistive-pulse sensing is effective for characterizing HBV capsid heterogeneity.
• Electric field strength is a critical parameter for optimizing the resolution and analysis of viral capsids.
• Understanding capsid electrophoretic mobility in confined geometries provides insights into viral assembly and transport mechanisms.