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Native Cell Membrane Nanoparticles System for Membrane Protein-Protein Interaction Analysis
Published on: July 16, 2020
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Structure and Interaction in the pH-Dependent Phase Behavior of Nanoparticle-Protein Systems
Indresh Yadav1,2, Sugam Kumar1, Vinod K Aswal1,2
1Solid State Physics Division, Bhabha Atomic Research Centre , Mumbai 400 085, India.
Langmuir : the ACS Journal of Surfaces and Colloids
|January 13, 2017
Summary
The study reveals how silica nanoparticle interactions with proteins lysozyme and bovine serum albumin (BSA) depend on pH. Lysozyme adsorbs strongly, while BSA does not, yet both induce nanoparticle aggregation above a critical protein concentration (CPC).
Area of Science:
- Colloid and surface science
- Nanomaterials science
- Biophysics
Background:
- Understanding nanoparticle-protein interactions is crucial for applications in drug delivery and biomaterials.
- Silica nanoparticles (18 nm) and model proteins (lysozyme, BSA) were chosen to investigate pH-dependent behavior.
Purpose of the Study:
- To elucidate the pH-dependent structure and interaction of anionic silica nanoparticles with cationic lysozyme and anionic BSA.
- To characterize the phase behavior and aggregation of nanoparticle-protein systems as a function of protein concentration and pH.
Main Methods:
- Dynamic Light Scattering (DLS) to measure nanoparticle size and aggregation.
- Small-Angle Neutron Scattering (SANS) to determine interaction potentials.
- Varying protein concentrations (0-5 wt%) at fixed silica nanoparticle concentration (1 wt%).
Main Results:
- Cationic lysozyme adsorbs strongly, with adsorption increasing as pH nears its isoelectric point (IEP).
- Anionic BSA shows no adsorption, irrespective of pH.
- Both systems transition from one-phase to two-phase above a critical protein concentration (CPC), which is higher for BSA.
- CPC increases for lysozyme and decreases for BSA as pH approaches their respective IEPs.
- Nanoparticle aggregation increases with protein concentration above CPC, suppressed by lysozyme and enhanced by BSA near their IEPs.
- SANS data reveals electrostatic repulsion and short-range attraction for lysozyme, and long-range attraction for BSA, explaining aggregation mechanisms (charge neutralization vs. depletion).
Conclusions:
- The study demonstrates distinct interaction mechanisms between anionic silica nanoparticles and oppositely charged lysozyme versus similarly charged BSA.
- pH significantly influences nanoparticle-protein interactions, driving aggregation through different pathways.
- The findings provide insights into controlling nanoparticle assembly and stability in complex biological environments.
