Temperature and oxidation-sensitive dioleoylphosphatidylethanolamine liposome stabilized with poly(ethyleneimine)/(phenylthio)acetic acid ion pair

Abstract

Temperature and oxidation-sensitive liposomes were prepared by stabilizing dioleoylphosphatidylethanolamine (DOPE) bilayers with the ion pair of poly(ethyleneimine)/(phenylthio)acetic acid (PEI/PTA). An upper critical solution temperature (UCST) behavior was observed when PEI/PTA ion pair was suspended in an aqueous solution. It was observed that the UCST increased with increasing PTA content. The ion pair was self-assembled into nanospheres owing to its amphiphilic property which was confirmed by transmission electron microscopy. The FT-IR spectroscopic spectrum showed that the ion pair formed a salt bridge between the amino group and the carboxyl group and the PTA content in the ion pair was readily oxidized by H₂O₂. Further, DOPE liposomal membranes could be stabilized with PEI/PTA ion pair. Due to the amphiphilic property, the ion pair played a role as a stabilizer for the formation of DOPE liposomes. The liposome released its payload in a temperature-responsive manner, possibly because when the temperature is raised, the ion pair loses its amphiphilic property and can be detached from the liposomal membrane. The liposome was also oxidation-responsive in terms of release, possibly because the amphiphilic property of the ion pair disappears when the PTA is oxidized.

Graphical Abstract

The schematic diagram of temperature and oxidation-sensitive DOPE liposome incorporating PEI/PTA ion pair.

Keywords:

• Dioleoylphosphatidylethanolamine
• poly(ethylene imine)
• (phenylthio)acetic acid
• temperature
• oxidation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. 2018R1A6A1A03025582). This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2022R1A2C2003353). This work was also supported by the Technology Innovation Program (20009663) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).