title: Novel reducible linear L-lysine-modified copolymers as efficient nonviral vectors.
abstract: The development of biodegradable gene delivery systems with high transfection efficiencies is paramount to the clinical translation of nonviral gene carriers. Therefore, to produce a biocompatible, reducible, effective and non-toxic gene delivery system, we have designed and synthesized novel reducible linear L-lysine modified copolymers (LLCs) as an alternative to high molecular weight poly(L-lysine) (PLL). The molecular weight (MW) of the copolymers was found to be approximately 3.2kDa with a polydispersity index of approximately 1.2. Gel retardation assays showed complete condensation of DNA at N/P ratios greater than 20/1 and exceptional LLC/pDNA polyplex stability during incubation with DNase I. Release of DNA from the polyplexes only occurred in the presence of the reducing agent dithiothreitol (DTT). The particle sizes of LLC/pDNA polyplexes were found to be between 100 and 231 nm with surface charges of 0.8-17 mV respectively. The transfection efficiencies of the polyplexes as determined with a luciferase assay showed that LLC polyplexes produced five times higher transfection efficiencies in HDF cells, three times higher transfection efficiencies in MCF-7 cells, and four times higher transfection efficiencies in MA cells as compared to the optimal PLL control. The LLC/pDNA polyplexes showed significantly lower cytotoxicities as compared to the control in HDF, MCF-7 and MA cells at certain N/P ratios. Therefore, these results suggest that these novel LLCs are efficient, reducible and biocompatible polymers for nonviral gene delivery.
authors.affiliation: Department of Pharmacological and Pharmaceutical Sciences, 1441 Moursund Street, University of Houston, Texas Medical Center Campus, Houston, Texas 77030, USA.
authors.forename: Mohamed Ismail
authors.initials: MI
authors.lastname: Nounou
authors.forename: Kalyopy
authors.initials: K
authors.lastname: Emmanouil
authors.forename: Samuel
authors.initials: S
authors.lastname: Chung
authors.forename: Thu
authors.initials: T
authors.lastname: Pham
authors.forename: Zhuoyuan
authors.initials: Z
authors.lastname: Lu
authors.forename: Malavosklish
authors.initials: M
authors.lastname: Bikram
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry*; D045744:Cell Line, Tumor; D002470:Cell Survival; D004247:DNA / Q000008:administration & dosage*; D006801:Humans; D008239:Lysine / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010957:Plasmids / Q000008:administration & dosage; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D014162:Transfection
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D004247:DNA; D008239:Lysine