Molecular exclusion limits for diffusion across a porous capsid.

Area of Science:

• Biophysics
• Nanotechnology
• Molecular Biology

Background:

• Molecular communication necessitates pores for transport and discrimination across barriers.
• Virus-like particles (VLPs) offer potential as nanoscale containers and transport systems.
• Accurate pore size characterization of dynamic VLPs is challenging.

Purpose of the Study:

• To investigate the size and charge selectivity of pores in bacteriophage P22 virus-like particles (VLPs).
• To determine the effective pore sizes of different P22 VLP morphologies.
• To understand how molecule size and charge affect diffusion into P22 VLPs.

Main Methods:

• Encapsulation of the enzyme AdhD within P22 VLPs.
• Utilizing a redox reaction with PAMAM dendrimer-modified NADH/NAD+ to probe pore accessibility.
• Analysis of diffusion across three distinct P22 VLP morphologies.

Main Results:

• Effective pore sizes for different P22 VLP structures were determined.
• Diffusion rates were correlated with molecule size and charge.
• Negatively charged substrates showed enhanced diffusion compared to neutral substrates, despite the VLP's negative exterior.

Conclusions:

• P22 VLPs exhibit size and charge-dependent molecular transport.
• The study provides insights into the dynamic pore characteristics of bacteriophage P22 VLPs.
• Findings have implications for designing VLP-based systems for molecular delivery and sensing.