Novel Oligo-Guanidyl-PEG Carrier Forming Rod-Shaped Polyplexes

Alessio Malfanti, Francesca Mastrotto, Yanxiao Han, Petr Král, Anna Balasso, Anna Scomparin, Sabina Pozzi, Ronit Satchi-Fainaro, Stefano Salmaso, Paolo Caliceti

Research output: Contribution to journalArticlepeer-review

Abstract

A novel unconventional supramolecular oligo-cationic structure (Agm 6 -M-PEG-OCH 3 ) has been synthesized to yield high efficiency therapeutic oligonucleotide (ON) delivery. Agm 6 -M-PEG-OCH 3 was obtained by a multistep protocol that included the conjugation of agmatine (Agm) moieties to maltotriose (M), which was further derivatized with one poly(ethylene glycol) (PEG) chain. Gel electrophoresis analysis showed that the 19 base pairs dsDNA model ON completely associates with Agm 6 -M-PEG-OCH 3 at 3 N/P molar ratio, which is in agreement with the in silico molecular predictions. Isothermal titration calorimetry (ITC) analyses showed that the Agm 6 -M-PEG-OCH 3 /ON association occurs through a combination of mechanisms depending on the N/P ratios resulting in different nanostructures. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the Agm 6 -M-PEG-OCH 3 /ON polyplexes have rod-shape structure with a mean diameter of 50-75 nm and aspect ratio depending on the N/P ratio. The polyplexes were stable over time in buffer, while a slight size increase was observed in the presence of serum proteins. Cell culture studies showed that neither Agm 6 -M-PEG-OCH 3 nor polyplexes displayed cytotoxic effects. Cellular uptake depended on the cell line and polyplex composition: cellular internalization was higher in the case of MCF-7 and KB cells compared to MC3T3-E1 cells and polyplexes with smaller aspect ratio were taken-up by cells more efficiently than polyplexes with higher aspect ratio. Finally, preliminary studies showed that our novel carrier efficiently delivered ONs into cells providing gene silencing.

Original languageEnglish
Pages (from-to)1678-1693
Number of pages16
JournalMolecular Pharmaceutics
Volume16
Issue number4
DOIs
StatePublished - 1 Apr 2019

Keywords

  • cationic carriers
  • nanoparticles
  • nonviral carriers
  • oligonucleotides delivery
  • polyplexes

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