PEI fluorination reduces toxicity and promotes liver-targeted siRNA delivery

Lian Xue, Yunfeng Yan, Petra Kos, Xiaoping Chen, Daniel J. Siegwart

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Polyethyleneimine (PEI) has been extensively investigated as an efficient carrier for nucleic acid delivery. Yet, it suffers from a high toxicity profile that hinders clinical translation. Fluorination has proven to be a valid approach to reduce the cytotoxicity of PEI and improve the in vitro siRNA delivery potency. Hydrophobicity and lipophobicity can be controllably introduced into the side chains of PEI. However, the effect of fluorination on siRNA delivery in vivo, particularly the biodistribution of siRNA polyplex nanoparticles with fluorinated PEIs, has not been extensively explored. Here, we introduce two series of fluorinated PEIs via amidation with ethyl trifluoroacetate and perfluorobutyryl chloride. Fluorination substantially improved the performance of PEI for siRNA delivery by reducing the cytotoxicity to MDA-MB-231 cells. Importantly, fluorinated PEI enabled the major accumulation of siRNA polyplex nanoparticles in the liver while non-fluorinated PEI delivered siRNA nanoparticles mainly to the lungs after intravenous administration to mice. It is envisioned that fluorination may be an important general strategy for lowering toxicity of cationic polymers, and that the fluorination-induced alteration of biodistribution may be applicable for improved delivery to different organs. [Figure not available: see fulltext.]

Original languageEnglish (US)
Pages (from-to)255-260
Number of pages6
JournalDrug Delivery and Translational Research
Issue number1
StatePublished - Feb 2021


  • Gene silencing
  • Nanoparticles
  • Polyethyleneimine (PEI)
  • siRNA

ASJC Scopus subject areas

  • Pharmaceutical Science


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