Chitosan and (Phenylthio) acetic acid-based ion pair self assembled for temperature and oxidation-responsive drug release

ABSTRACT

Chitosan (CTSN), a cationic biopolymer was used to prepare Ion pair self-assembly (IPSAM) with (phenylthio)acetic acid (PTA) as hydrophobic counter ion which is responsive to temperature and oxidation. The IPSAM was formed when the amino to carboxylic group molar ratio was 1/9 ~ 4/6. CTSN/PTA IPSAM was found as sphere-like nanoparticles whose diameter was 30–50 nm on TEM image. The ion pair showed the upper critical solution temperature (UCST) that increased with increasing PTA content and decreased when PTA of the ion pair was oxidized by H₂O₂. The ion pair exhibited amphiphilic property which was responsible for interface activity which decline upon the oxidation of the PTA. The surface tension was low for the ratio of CTSN/PTA (3/7), which made the 3/7 ratio suitable for further studies. The ionic interaction between CTSN and PTA and the oxidation of PTA were confirmed by FT-IR spectroscopy. The payload’s release (i.e. Nile red) in IPSAM was constrained below the UCST but it was prompted above the phase transition temperature possibly due to the disassembly of the IPSAM and PTA oxidation. The release was found to be higher in tumor environment temperature in the presence of H₂O₂ indicating the release was dependent on temperature and oxidation.

KEYWORDS:

• IPSAM
• Chitosan (CTSN)
• (Phenylthio) acetic acid

Disclosure Statement

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

Author Contributions

JCK: Conceptualization, Funding acquisition, Project administration, Resources, Validation. JGJ: Data curation, Formal analysis, Investigation, Visualization, Writing – original draft preparation, Writing – review & editing. All authors read and approved the final manuscript.

Data Availability Statement

All relevant data are included in the manuscript. Data can be available from the corresponding author upon request.

Human or Animal Rights

This article does not contain any studies with human participants or animals performed by any of the authors.

Supplementary Material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/1539445X.2024.2303110

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].