title: [Small interfering RNA delivery mediated by mPEG-PCL-g-PEI polymer nanoparticles].
abstract: The aim of this paper is to report the synthesis of the mPEG-PCL-g-PEI copolymers as small interfering RNA (siRNA) delivery vector, and exploration of the siRNA delivery potential of mPEG-PCL-g-PEI in vitro. The diblock copolymers mPEG-PCL-OH was prepared through the ring-opening polymerization. Then, the hydroxyl terminal (-OH) of mPEG-PCL-OH was chemically converted into the carboxy (-COOH) and N-hydroxysuccinimide (NHS) in turn to prepare mPEG-PCL-NHS. The branched PEI was reacted with mPEG-PCL-NHS to synthesize the ternary copolymers mPEG-PCL-g-PEI. The structure of mPEG-PCL-g-PEI copolymers was characterized with Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The mPEG-PCL-g-PEI/siRNA nanoparticles were prepared by complex coacervation, and the nanoparticles size and zeta potential were determined, separately. The cytotoxicities of mPEG-PCL-g-PEI/siRNA nanoparticles and PEI/siRNA nanoparticles were compared through cells MTT assays in vitro. The inhibition efficiencies of firefly luciferase gene expression by mPEG-PCL-g-PEI/ siRNA nanoparticle at various N/P ratios were investigated through cell transfection in vitro. The experimental results suggested that the ternary (mPEG5k-PCL(1.2k))1.4-g-PEI(10k) copolymers were successfully synthesized. (mPEG(5k)-PCL(1.2k))1.4-g-PEI(10k) could condense siRNA into nanoparticles (50-200 nm) with positive zeta potential. MTT assay results showed that the cytotoxicity of (mPEG(5k)-PCL(1.2k))1.4-g-PEI(10k)/siRNA nanoparticles was significantly lower than that of PEI(10k)/siRNA nanoparticles (P < 0.05). The expression of firefly luciferase gene could be significantly down-regulated at a range of N/P ratio from 50 to 150 (P < 0.01), and maximally inhibited at the N/P ratio of 125. The mPEG-PCL-g-PEI polymers could delivery siRNA into cells to inhibit the expression of target gene with very low cytotoxicity, which suggested that mPEG-PCL-g-PEI could serve as a new type of siRNA delivery vector.
authors.affiliation: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Ming
authors.initials: M
authors.lastname: Lü
authors.forename: Zhong-Gao
authors.initials: ZG
authors.lastname: Gao
authors.forename: Ming-Ji
authors.initials: MJ
authors.lastname: Jin
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Yang
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival; D004337:Drug Carriers; D017930:Genes, Reporter; D005822:Genetic Vectors; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D008970:Molecular Weight; D053758:Nanoparticles; D010316:Particle Size; D011091:Polyesters / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D004337:Drug Carriers; D011091:Polyesters; D011108:Polymers; D034741:RNA, Small Interfering; C439611:methoxy poly(ethylene glycol-co-epsilon-caprolactone); D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D008156:Luciferases