Dna complexation by cationic pullulan possessing thermo-sensitive units

M. Constantin, I. Oanea, V. Harabagiu, P. Ascenzi, G. Fundueanu

Research output: Contribution to journalArticlepeer-review


Cationic pullulan (PN) with pendant thermo-responsive units were complexed with DNA to obtain a potential thermo-sensitive gene carrier. Semitelechelic oligomers of N-isopropylacrylamide/N,N-dim ethylacrylamide possessing -COOH end groups and a lower critical solution temperature of about 36 °C at pH = 7.4 (50 mM phosphate buffer) were prepared by free radical polymerization in the presence of mercaptopropionic acid as the chain transfer agent. Then, the functionalized pullulan with cationic groups was coupled with thermo-responsive oligomers by reaction between the -COOH end groups of oligomers and the remaining-OH groups of PN. Lastly, the thermo-responsive cationic pullulan chains were complexed with DNA at different charge (+/-) ratios. The size of the complexes ranges between 160 and 510 nm depending on the polymer/DNA charge ratio and temperature. The complexes obtained at a charge (+/-) ratio of 5/1 showing a diameter <200 nm, were stable in the presence of bovine serum albumin, and were unaffected by nuclease degradation.

Original languageEnglish
Pages (from-to)849-861
Number of pages13
JournalDigest Journal of Nanomaterials and Biostructures
Issue number2
Publication statusPublished - 2011


  • DNA complexes
  • Poly(N-isopropylacrylamide) copolymers
  • Potential gene carrier
  • Pullulan
  • Smart polymers

ASJC Scopus subject areas

  • Materials Science(all)
  • Biomedical Engineering
  • Physical and Theoretical Chemistry
  • Condensed Matter Physics
  • Structural Biology
  • Atomic and Molecular Physics, and Optics


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