title: Intercalating quaternary nicotinamide-based poly(amido amine)s for gene delivery.
abstract: In the development of potent polymeric gene carriers for gene therapy, a good interaction between the polymer and the nucleotide is indispensable to form small and stable polyplexes. Polymers with relatively high cationic charge density are frequently used to provide these interactions, but high cationic charge is usually associated with severe cytotoxicity. In this study an alternative, nucleotide specific binding interaction based on intercalation was investigated to improve polymer/pDNA complex formation. For this purpose bioreducible poly(amido amine) copolymers (p(CBA-ABOL/Nic)) were synthesized with different degrees of intercalating quaternary nicotinamide (Nic) groups and amide-substituted derivatives in their side chains. The quaternary nicotinamide group was chosen as intercalating moiety because this group is part of the naturally occurring NAD+ coenzyme and is therefore expected to be non-toxic and non-carcinogenic. The presence of the quaternary nicotinamide moieties in the poly(amido amine) copolymers showed to effectively promote self-assembled polyplex formation already at low polymer/DNA ratios and results in decreased polyplex size and increased stability of the polyplexes. Furthermore, in contrast to the primary amine functionalized analogs the quaternary nicotinamide polymers showed to be non-hemolytic, indicating their compatibility with cell membranes. Polymers with 25% of Nic in the side chains induced GFP expressions of about 4-5 times that of linear PEI, which is comparable with p(CBA-ABOL), the parent PAA without Nic, but at a two- to fourfold lower required polymer dose. N-phenylation of the nicotinamide functionality even further reduces the required polymer dose to form stable polyplexes, which is a major improvement for these kinds of cationic polymers.
authors.affiliation: Department of Controlled Drug Delivery, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: L J
authors.initials: LJ
authors.lastname: van der Aa
authors.affiliation: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Science (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands; Department of Clinical Chemistry and Hematology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Vader
authors.affiliation: Department of Controlled Drug Delivery, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands; Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Science (UIPS), Utrecht University, P.O. Box 80082, 3508 TB Utrecht, The Netherlands.
authors.forename: G
authors.initials: G
authors.lastname: Storm
authors.affiliation: Department of Clinical Chemistry and Hematology, University Medical Center Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.
authors.forename: R M
authors.initials: RM
authors.lastname: Schiffelers
authors.affiliation: Department of Controlled Drug Delivery, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. Electronic address: j.f.j.engbersen@utwente.nl.
authors.forename: J F J
authors.initials: JF
authors.lastname: Engbersen
mesh_terms: D000818:Animals; D019556:COS Cells; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D004247:DNA / Q000008:administration & dosage / Q000737:chemistry; D004912:Erythrocytes / Q000187:drug effects; D015870:Gene Expression; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D007364:Intercalating Agents / Q000008:administration & dosage / Q000737:chemistry; D009536:Niacinamide / Q000008:administration & dosage / Q000737:chemistry; D010957:Plasmids; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry
chemical_list: D007364:Intercalating Agents; D011108:Polymers; D049452:Green Fluorescent Proteins; D009536:Niacinamide; D004247:DNA
keywords: Intercalation; Nicotinamide cation; Poly(amido amine); Polyplex; Quaternary nicotinamide; Transfection