title: Mechanistic profiling of the siRNA delivery dynamics of lipid-polymer hybrid nanoparticles.
abstract: Understanding the delivery dynamics of nucleic acid nanocarriers is fundamental to improve their design for therapeutic applications. We investigated the carrier structure-function relationship of lipid-polymer hybrid nanoparticles (LPNs) consisting of poly(DL-lactic-co-glycolic acid) (PLGA) nanocarriers modified with the cationic lipid dioleoyltrimethyl-ammoniumpropane (DOTAP). A library of siRNA-loaded LPNs was prepared by systematically varying the nitrogen-to-phosphate (N/P) ratio. Atomic force microscopy (AFM) and cryo-transmission electron microscopy (cryo-TEM) combined with small angle X-ray scattering (SAXS) and confocal laser scanning microscopy (CLSM) studies suggested that the siRNA-loaded LPNs are characterized by a core-shell structure consisting of a PLGA matrix core coated with lamellar DOTAP structures with siRNA localized both in the core and in the shell. Release studies in buffer and serum-containing medium combined with in vitro gene silencing and quantification of intracellular siRNA suggested that this self-assembling core-shell structure influences the siRNA release kinetics and the delivery dynamics. A main delivery mechanism appears to be mediated via the release of transfection-competent siRNA-DOTAP lipoplexes from the LPNs. Based on these results, we suggest a model for the nanostructural characteristics of the LPNs, in which the siRNA is organized in lamellar superficial assemblies and/or as complexes entrapped in the polymeric matrix.
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen O, Denmark.
authors.forename: Stefano
authors.initials: S
authors.lastname: Colombo
authors.affiliation: Department of Pharmaceutical Sciences, Shenyang Pharmaceutical University, Shenyang, Wenhua Road 103, 110016, China. Electronic address: cundongmei@163.com.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Cun
authors.affiliation: Biophotonic Imaging Group, Lab of General Biochemistry and Physical Pharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Remaut
authors.affiliation: Molecular Profiles Ltd, 8 Orchard Place, Nottingham Business Park, Nottingham NG8 6PX, UK.
authors.forename: Matt
authors.initials: M
authors.lastname: Bunker
authors.affiliation: Molecular Profiles Ltd, 8 Orchard Place, Nottingham Business Park, Nottingham NG8 6PX, UK.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen O, Denmark.
authors.forename: Birte
authors.initials: B
authors.lastname: Martin-Bertelsen
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen O, Denmark.
authors.forename: Anan
authors.initials: A
authors.lastname: Yaghmur
authors.affiliation: Biophotonic Imaging Group, Lab of General Biochemistry and Physical Pharmacy, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium; Centre for Nano- and Biophotonics, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
authors.forename: Kevin
authors.initials: K
authors.lastname: Braeckmans
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen O, Denmark. Electronic address: hanne.morck@sund.ku.dk.
authors.forename: Hanne M
authors.initials: HM
authors.lastname: Nielsen
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen O, Denmark.
authors.forename: Camilla
authors.initials: C
authors.lastname: Foged
mesh_terms: D045744:Cell Line, Tumor; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D005229:Fatty Acids, Monounsaturated; D000644:Quaternary Ammonium Compounds; D034741:RNA, Small Interfering; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane
keywords: DOTAP; Drug delivery; Nanomedicine; PLGA; Sustained release; siRNA