title: Thermo-sensitive nanoparticles for triggered release of siRNA.
abstract: Efficient delivery of small interfering RNA (siRNA) is crucially required for cancer gene therapy. Herein, a thermo-sensitive copolymer with a simple structure, poly (ethylene glycol) methyl ether acrylate-b-poly (N-isopropylacrylamide) (mPEG-b-PNIPAM) was developed. A novel kind of thermo-sensitive nanoparticles (DENPs) was constructed for the cold-shock triggered release of siRNA by double emulsion-solvent evaporation method using mPEG-b-PNIPAM and a cationic lipid, 3β [N-(N', N'-dimethylaminoethane)-carbamoyl] cholesterol [DC-Chol]. DENPs were observed by transmission electron microscopy and dynamical light scattering before and after 'cold shock' treatment. The encapsulation efficiency (EE) of siRNA in DENPs, which was measured by fluorescence spectrophotometer was 96.8% while it was significantly reduced to be 23.2% when DC-Chol was absent. DENPs/siRNA NPs exhibited a thermo-sensitive siRNA release character that the cumulatively released amount of siRNA from cold shock was approximately 2.2 folds higher after 7 days. In vitro luciferase silencing experiments indicated that DENPs showed potent gene silencing efficacy in HeLa-Luc cells (HeLa cells steadily expressed luciferase), which was further enhanced by a cold shock. Furthermore, MTT assay showed that cell viability with DENPs/siRNA up to 200 nM remained above 80%. We also observed that most of siRNA was accumulated in kidney mediated by DENPs instead of liver and spleen in vivo experiments. Thus, DENPs as a cold shock responsive quick release model for siRNA or hydrophilic macromolecules delivery provide a new way to nanocarrier design and clinic therapy.
authors.affiliation: a Key Laboratory of Systems Bioengineering of the Ministry of Education, Department of Polymer Science and Technology, School of Chemical Engineering and Technology , Tianjin University , Tianjin 300072 , China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Yang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cheng
authors.forename: Qian
authors.initials: Q
authors.lastname: Jiang
authors.forename: Liandong
authors.initials: L
authors.lastname: Deng
authors.forename: Zicai
authors.initials: Z
authors.lastname: Liang
authors.forename: Anjie
authors.initials: A
authors.lastname: Dong
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000818:Animals; D002470:Cell Survival; D002784:Cholesterol / Q000031:analogs & derivatives / Q000737:chemistry; D015316:Genetic Therapy / Q000295:instrumentation; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000378:metabolism; D012997:Solvents / Q000737:chemistry; D013154:Spleen / Q000378:metabolism; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D011108:Polymers; D034741:RNA, Small Interfering; D012997:Solvents; C070648:3-(N-(N',N'-dimethylaminoethane)carbamoyl)cholesterol; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols; C028210:monomethoxypolyethylene glycol; D002784:Cholesterol; D008156:Luciferases
keywords: PNIPAM; cold shock; double emulsion–solvent evaporation method; siRNA; thermo-sensitive nanoparticles