Measuring zeta potential of protein nano-particles using electroacoustics
1Dispersion Technology Inc, 364 Adams Street, Bedford Hills, NY 10507, USA.
Colloids and Surfaces. B, Biointerfaces
|July 9, 2014
Summary
Electroacoustic spectroscopy accurately measures protein zeta potential in high ionic strength solutions. This method avoids heat effects and sample dilution, offering a simpler alternative to traditional techniques.
Area of Science:
- Colloid and Surface Science
- Biophysical Chemistry
Background:
- Traditional electrophoretic methods for measuring zeta potential are complicated by heat effects in high ionic strength solutions.
- Electrophoretic methods also require dilution of concentrated protein dispersions, which can alter their properties.
Purpose of the Study:
- To present electroacoustic measurements of bovine serum albumin (BSA) zeta potential in aqueous solutions.
- To investigate the dependence of BSA zeta potential on ionic strength, pH, and Ca(2+) ion concentration.
Main Methods:
- Electroacoustic spectroscopy was employed to measure zeta potential.
- Measurements were performed on 5wt.% BSA suspensions (median particle size ~180nm) across a wide range of salt molarities (up to 0.5mol/L).
- Dialysis was used for low ionic strength measurements, and pH and Ca(2+) titrations were conducted.
Main Results:
- Zeta potential was measured for BSA nanoparticles in solutions with ionic strengths up to 0.5mol/L.
- The study successfully mapped the zeta potential's dependence on ionic strength, pH, and divalent cations.
- Results showed good agreement with available published data.
Conclusions:
- Electroacoustic spectroscopy provides a robust and simple method for determining protein zeta potential, even in challenging physiological conditions.
- The technique is suitable for concentrated protein dispersions and avoids thermal artifacts common in other methods.
- This study validates electroacoustic spectroscopy for characterizing protein nanoparticle behavior in varying solution chemistries.
