title: Synthesis and conformational evaluation of a novel gene delivery vector for human mesenchymal stem cells.
abstract: We have synthesized a novel gene delivery vector by covalently combining branched polyethylenimine (bPEI) and hyaluronic acid (HA) with the aim of improving transfection of bPEI into human mesenchymal stem cells (hMSCs) while maintaining cell viability. Because of the opposite charges on bPEI and HA, the bPEI-HA vector forms a zwitterionic polymer capable of inter- and intramolecular interactions. We have characterized the hydrodynamic radius of bPEI-HA and bPEI-HA/DNA complexes at ambient and physiological temperatures, as well as at a range of salt concentrations using light scattering, and investigated the effect of the size of transfecting complexes on gene delivery. We found that by increasing the salt concentration from 150 to 1000 mM of NaCl, the mean hydrodynamic radius (R(h)) of bPEI-HA increases from 2.0 +/- 1.1 to 366.0 +/- 149.0 nm. However, increasing the salt concentration decreases the mean R(h) of bPEI-HA/DNA complexes from 595.0 +/- 44.6 to 106.0 +/- 19.2 nm at 25 degrees C and from 767.0 +/- 137.2 to 74.0 +/- 23.0 nm at 37 degrees C. hMSCs transfected with smaller complexes showed a significant increase in transfection from 3.8 +/- 1.5% to 19.1 +/- 4.4%. Similarly, bPEI-HA performed significantly better than bPEI in terms of cell viability (86.0 +/- 6.7% with bPEI-HA versus 7.0 +/- 2.8% with bPEI, 24 h post exposure at the highest concentration of 500 mg/mL) and maximum transfection efficiencies (12.0 +/- 4.2% with bPEI/DNA complexes and 33.6 +/- 13.9% with bPEI-HA/DNA complexes). Thus, modifying bPEI by covalent conjugation with HA improves its performance as a gene delivery vector in hMSCs. This presents a promising approach to altering hMSCs for tissue engineering and other applications.
authors.affiliation: Department of Bioengineering, Rice University, MS-142, P.O. Box 1892, Houston, Texas 77251-1892, USA.
authors.forename: Anita
authors.initials: A
authors.lastname: Saraf
authors.forename: Michael C
authors.initials: MC
authors.lastname: Hacker
authors.forename: Balaji
authors.initials: B
authors.lastname: Sitharaman
authors.forename: K Jane
authors.initials: KJ
authors.lastname: Grande-Allen
authors.forename: Michael A
authors.initials: MA
authors.lastname: Barry
authors.forename: Antonios G
authors.initials: AG
authors.lastname: Mikos
mesh_terms: D004247:DNA / Q000737:chemistry / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D005822:Genetic Vectors / Q000138:chemical synthesis / Q000737:chemistry* / Q000633:toxicity; D006801:Humans; D006820:Hyaluronic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D008024:Ligands; D008027:Light; D059630:Mesenchymal Stem Cells; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011094:Polyethyleneimine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D012542:Scattering, Radiation; D012965:Sodium Chloride / Q000737:chemistry; D014162:Transfection
chemical_list: D008024:Ligands; C528056:branched polyethylenimine-hyaluronic acid; D012965:Sodium Chloride; D011094:Polyethyleneimine; D006820:Hyaluronic Acid; D004247:DNA