End-chain fluorination of polyesters favors perfluorooctyl bromide encapsulation into echogenic PEGylated nanocapsules

Perfluorinated end-capped polylactides (PLAs) with various perfluorinated chain lengths from C 3 F 7 to C 13 F 27 were synthesized and formulated into PEGylated nanocapsules of perfluorooctyl bromide (PFOB) to be used as ultrasound contrast agents (UCAs). We show that the perfluorinated end groups d...

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Bibliographic Details
Published inPolymer chemistry Vol. 8; no. 16; pp. 2559 - 2570
Main Authors Houvenagel, Sophie, Picheth, Guilherme, Dejean, Camille, Brûlet, Annie, Chennevière, Alexis, Couture, Olivier, Huang, Nicolas, Moine, Laurence, Tsapis, Nicolas
Format Journal Article
LanguageEnglish
Published Royal Society of Chemistry - RSC 28.04.2017
Subjects
Bromides
Chains (polymeric)
Chemical Sciences
Contrast agents
Encapsulation
Fluorination
In vitro testing
Nanostructure
Ultrasound
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Summary:Perfluorinated end-capped polylactides (PLAs) with various perfluorinated chain lengths from C 3 F 7 to C 13 F 27 were synthesized and formulated into PEGylated nanocapsules of perfluorooctyl bromide (PFOB) to be used as ultrasound contrast agents (UCAs). We show that the perfluorinated end groups do not reduce the interfacial tension between PFOB and the organic solvent used during formulation and do not allow a significant reduction of shell thickness (Small angle neutron scattering (SANS) experiments). However, the PFOB encapsulation efficiency increases with the fluorinated chain length until C 8 F 17 . This suggests the possible presence of favorable fluorophilic interactions between PFOB and perfluorinated end groups. In addition, nanocapsules formulated with different fluorinated polymers do not promote any specific toxicity in vitro compared to non-fluorinated PLAs. Ultrasound imaging performed on samples presenting the lowest thickness values, namely nanocapsules made from 50% PLA-C 6 F 13 /50% polylactide- b -poly(ethylene glycol) (PLA-PEG) and pure PLA-PEG nanocapsules, shows that fluorinated nanocapsules exhibit a higher ultrasound contrast enhancement in vitro most probably thanks to the higher PFOB content and density arising from polymer fluorination. This highlights the benefit of fluorination for improving the echogenicity of nano-sized ultrasound contrast agents.
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ISSN:1759-9954
1759-9962
DOI:10.1039/C7PY00400A