Disassembly of layer-by-layer films of plasmid DNA and reducible TAT polypeptide

Jenifer Blacklock, Hitesh Handa, Devika Soundara Manickam, Guangzhao Mao, Ashis Mukhopadhyay, David Oupický

Research output: Contribution to journalArticlepeer-review

78 Scopus citations


This paper reports the disassembly of layer-by-layer (LbL) films of plasmid DNA and a reducible cationic polypeptide. To utilize a reducing microenvironment of cellular plasma membrane as a potential trigger, LbL films are assembled to contain both DNA and the TAT-based polypeptide (PTAT) with reducible disulfide bonds in the backbone. The assembly and disassembly processes are monitored by goniometry, ellipsometry, and atomic force microscopy (AFM). The structure of the PTAT films is compared with that of non-reducible poly(l-lysine) (PLL) films. Both PTAT and PLL films exhibit exponential growth but with the contact angle alternating between characteristic values. Ellipsometry and AFM show a gradual and complete disassembly of the PTAT but not the PLL films in a 24 h period in the reducing environment in vitro. This study suggests a potential of using reducible LbL films for controlled DNA delivery.

Original languageEnglish (US)
Pages (from-to)117-124
Number of pages8
Issue number1
StatePublished - Jan 2007
Externally publishedYes


  • DNA
  • Gene delivery
  • Layer-by-layer
  • PLL
  • Polyelectrolytes
  • TAT

ASJC Scopus subject areas

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials

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