title: Quaternized starch-based carrier for siRNA delivery: from cellular uptake to gene silencing.
abstract: RNAi therapeutics is a powerful tool for treating diseases by sequence-specific targeting of genes using siRNA. Since its discovery, the need for a safe and efficient delivery system for siRNA has increased. Here, we have developed and characterized a delivery platform for siRNA based on the natural polysaccharide starch in an attempt to address unresolved delivery challenges of RNAi. Modified potato starch (Q-starch) was successfully obtained by substitution with quaternary reagent, providing Q-starch with cationic properties. The results indicate that Q-starch was able to bind siRNA by self-assembly formation of complexes. For efficient and potent gene silencing we monitored the physical characteristics of the formed nanoparticles at increasing N/P molar ratios. The minimum ratio for complete entrapment of siRNA was 2. The resulting complexes, which were characterized by a small diameter (~30 nm) and positive surface charge, were able to protect siRNA from enzymatic degradation. Q-starch/siRNA complexes efficiently induced P-glycoprotein (P-gp) gene silencing in the human ovarian adenocarcinoma cell line, NCI-ADR/Res (NAR), over expressing the targeted gene and presenting low toxicity. Additionally, Q-starch-based complexes showed high cellular uptake during a 24-hour study, which also suggested that intracellular siRNA delivery barriers governed the kinetics of siRNA transfection. In this study, we have devised a promising siRNA delivery vector based on a starch derivative for efficient and safe RNAi application.
authors.affiliation: Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Eliz
authors.initials: E
authors.lastname: Amar-Lewis
authors.affiliation: Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Aharon
authors.initials: A
authors.lastname: Azagury
authors.affiliation: Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chintakunta
authors.affiliation: Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Riki
authors.initials: R
authors.lastname: Goldbart
authors.affiliation: Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
authors.forename: Tamar
authors.initials: T
authors.lastname: Traitel
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Jackson
authors.initials: J
authors.lastname: Prestwood
authors.affiliation: Laboratory of Nanomedicine, Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv 69978, Israel; Department of Materials Science and Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel; Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Dalit
authors.initials: D
authors.lastname: Landesman-Milo
authors.affiliation: Laboratory of Nanomedicine, Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv 69978, Israel; Department of Materials Science and Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel; Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Dan
authors.initials: D
authors.lastname: Peer
authors.affiliation: Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel. Electronic address: kost@bgu.ac.il.
authors.forename: Joseph
authors.initials: J
authors.lastname: Kost
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics*; D045744:Cell Line, Tumor; D004337:Drug Carriers / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D053758:Nanoparticles; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics; D013213:Starch / Q000737:chemistry*; D014162:Transfection
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004337:Drug Carriers; D034741:RNA, Small Interfering; D013213:Starch
keywords: Drug delivery; Polysaccharide; Quaternized starch; Self-assembly complexes; Small interfering RNA