Format

Send to

Choose Destination
Anal Bioanal Chem. 2017 Sep;409(24):5779-5787. doi: 10.1007/s00216-017-0527-z. Epub 2017 Jul 31.

Zeta potential: a case study of cationic, anionic, and neutral liposomes.

Author information

1
Nanotechnology Characterization Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA.
2
Nanotechnology Characterization Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, 21702, USA. Jeffrey.Clogston@nih.gov.

Abstract

Zeta potential is often used to approximate a nanoparticle's surface charge, i.e., cationic, anionic, or neutral character, and has become a standard characterization technique to evaluate nanoparticle surfaces. While useful, zeta potential values provide only very general conclusions about surface charge character. Without a thorough understanding of the measurement parameters and limitations of the technique, these values can become meaningless. This case study attempts to explore the sensitivity of zeta potential measurement using specifically formulated cationic, anionic, and neutral liposomes. This study examines zeta potential dependence on pH and ionic strength, resolving power, and highlights the sensitivity of zeta potential to charged liposomes. Liposomes were prepared with cholesterol, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), and varying amounts of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS). A strong linear relationship was noted between zeta potential values and the mole percentage of charged lipids within a liposome (e.g., cationic DOTAP or anionic DOPS). This finding could be used to formulate similar liposomes to a specific zeta potential, potentially of importance for systems sensitive to highly charged species. In addition, cationic and anionic liposomes were titrated with up to two mole percent of the neutral lipid 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (lipid-PEG; LP). Very small amounts of the lipid-PEG (<0.2 mol%) were found to impart stability to the DOTAP- and DOPS-containing liposomes without significantly affecting other physicochemical properties of the formulation, providing a simple approach to making stable liposomes with cationic and anionic surface charge.

KEYWORDS:

Lipid-PEG; Liposomes; Stability; Surface characterization; Zeta potential

PMID:
28762066
DOI:
10.1007/s00216-017-0527-z
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center