Intelligent biosynthetic nanobiomaterials (IBNs) for hyperthermic gene delivery

Tze Haw Howard Chen, Younsoo Bae, Darin Y. Furgeson

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


Purpose. Intelligent biosynthetic nanobiomaterials (IBNs) were constructed as recombinant diblock copolymers, notated as K8-ELP(1-60), containing a cationic oligolysine (VGK8G) and a thermosensitive elastin-like polypeptide (ELP) block with 60 repetitive pentapeptide units [(VPGXG)60; X is Val, Ala and Gly in a 5:2:3 ratio]. Methods. K 8-ELP(1-60) was synthesized by recursive directional ligation for DNA oligomerization. Purity and molecular weight of K8-ELP(1-60) were confirmed by SDS-PAGE and mass spectrometry. DNA polyplexes were prepared from K8-ELP(1-60) and pGL3-Control (pGL3-C) plasmid DNA (pDNA) and stability was evaluated by gel retardation, DLS, and DNA displacement with heparin. Thermal transition profiles were studied by measuring the turbidity change at 350 nm and the polyplexes were used to transfect MCF-7 cells with a concomitant cytotoxicity assay. Results. SDS-PAGE and MALDI-TOF studies showed highly pure copolymers at the desired molecular weight. K8-ELP(1-60) condensed pDNA at a cation to anion (N/P) ratio above 0.25 with a tight distribution of particle size ranging from 115.5-32.4 nm with increasing N/P ratio. Thermal transition temperatures of K8-ELP(1-60)/pDNA and K8-ELP(1-60) alone were 44.9 and 71.5°C, respectively. K 8-ELP(1-60)/pDNA complexes successfully transduced MCF-7 cells with qualitative expression of enhanced green fluorescent protein (EGFP) and minimal cytotoxicity compared to branched poly(ethyleneimine) controls. Conclusions. K8-ELP(1-60) was successfully designed and purified through recombinant means with efficient and stable condensation of pDNA at N/P ratios >0.25 and polyplex particle size <115 nm. MCF-7 cells successfully expressed EGFP with minimal cytotoxicity compared to positive controls; moreover, polyplexes retained sharp, thermotransitive kinetics within a narrow Tt range at clinically relevant hyperthermic temperatures, where the decrease of Tt was due to the increased hydrophobicity upon charge neutralization.

Original languageEnglish
Pages (from-to)683-691
Number of pages9
JournalPharmaceutical Research
Issue number3
StatePublished - Mar 2008

Bibliographical note

Funding Information:
This work was funded by University of Wisconsin-Madison start-up funds to DYF. The ELP(1–30) gene was donated by Prof. Ashutosh Chilkoti (Duke University). We thank Prof. Glen Kwon (University of Wisconsin—Madison) for use of the NICOMP DLS; Prof. Maureen Barr (University of Wisconsin—Madison) for microscope access; and the UW Biotechnology Center for performing MALDI-TOF mass spectrum analysis. We express our thanks to Ms. Tracy P. Williamson for her critical review of the manuscript.


  • Elastin-like polypeptide
  • Gene delivery
  • Gene vector
  • Hyperthermia
  • Intelligent polymer
  • Nanobiomaterial

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)


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