Complexation of Poly(ethylene glycol)-(ds)OligoDNA Conjugates with Ionic Liquids

Young Hun Kim; Nayeong Jeon; Sujin Park; Siyoung Q Choi; Eunji Lee; Sheng Li

doi:10.1021/acsmacrolett.4c00028

Complexation of Poly(ethylene glycol)-(ds)OligoDNA Conjugates with Ionic Liquids

ACS Macro Lett. 2024 Apr 17:528-536. doi: 10.1021/acsmacrolett.4c00028. Online ahead of print.

Authors

Young Hun Kim¹, Nayeong Jeon², Sujin Park¹, Siyoung Q Choi¹, Eunji Lee², Sheng Li¹

Affiliations

¹ Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
² School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.

PMID: 38629344
DOI: 10.1021/acsmacrolett.4c00028

Abstract

We report the complexation of poly(ethylene glycol) conjugated double-stranded oligoDNA (PEG-(ds)oligoDNA) with imidazolium-based ionic liquids (ILs) to form polyelectrolyte complex aggregates (PCAs). The PEG-(ds)oligoDNA conjugates are prepared following a solution-phase coupling reaction. The binding of PEG-(ds)oligoDNA with either 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF₄]) or 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM][BF₄]) is confirmed by a fluorescence displacement assay. Both ILs show stronger binding affinity to PEG-(ds)oligoDNA than bare (ds)oligoDNA due to the PEG-assisted increase in IL cation concentration in the vicinity of (ds)oligoDNA. The complex morphology formed at various amine (N) to phosphate (P) ratios is also examined. At high N/P ratios above 4, nanosized PCAs are formed, driven by a counterion-mediated attraction among the IL-bound (ds)oligoDNA segments and stabilized by the conjugated PEG segments. The PCAs exhibit near-neutral surface charges and resistance to DNase degradation, suggesting their potential use in gene delivery applications.