title: Thermally triggered cellular uptake of quantum dots immobilized with poly(N-isopropylacrylamide) and cell penetrating peptide.
abstract: Thermally sensitive quantum dots (TSQDs) that exhibit an "on-demand" cellular uptake behavior via temperature-induced "shielding/deshielding" of cell penetrating peptides (CPP) on the surface were fabricated. Poly(N-isopropylacrylamide) (PNIPAAm) (M(w) = 11.5K) and CPP were biotinylated at their terminal ends and co-immobilized on to the surface of streptavidin-coated quantum dots (QDs-Strep) through biotin-streptavidin interaction. The cellular contact of CPP was sterically hindered due to hydrated PNIPAAm chains below the lower critical solution temperature (LCST). In contrast, above the LCST, grafted PNIPAAm chains were collapsed to make CPP moieties resurfaced, leading to increased cellular uptake of QDs. The temperature-controlled "shielding/deshielding" of CPP was further applied for a thermally triggered siRNA delivery system, where biotinylated siRNA was additionally conjugated to the surface of TSQDs. The level of gene silencing was significantly enhanced by increasing temperature above the LCST due to the surface exposure of CPP.
authors: Department of Biological Sciences and Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea.
authors: Chunsoo
authors: C
authors: Kim
authors: Yuhan
authors: Y
authors: Lee
authors: Jee Seon
authors: JS
authors: Kim
authors: Ji Hoon
authors: JH
authors: Jeong
authors: Tae Gwan
authors: TG
authors: Park
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins; D001483:Base Sequence; D001692:Biological Transport; D045744:Cell Line, Tumor; D057846:Cell-Penetrating Peptides / Q000737:chemistry* / Q000378:metabolism*; D020868:Gene Silencing; D006801:Humans; D036103:Nanotechnology; D011108:Polymers / Q000737:chemistry*; D045663:Quantum Dots; D034741:RNA, Small Interfering / Q000235:genetics; D013696:Temperature
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D057846:Cell-Penetrating Peptides; D011108:Polymers; D034741:RNA, Small Interfering; C052970:poly-N-isopropylacrylamide