*2.1. Reagents and Materials*

2-(*N*-morpholino)ethanesulfonic acid (MES, Sigma-Adrich, Darmstadt, Germany), 3-aminopropyltriethoxysilane (APTES, Sigma-Adrich), 3-mercaptopropyl triethoxysilane (MPTES, >95%, Sigma-Adrich), ammonium fluoride (NH4F, >98% Fluka, Darmstadt, Germany), Atto 633-carboxy dye (Atto-Tec, Siegen, Germany), <sup>4</sup>,6-diamidino-2-phenylindole (DAPI, Thermo Fisher, Schwerte, Germany), block copolymer surfactant (Pluronic F127 (EO106PO70EO106), Sigma-Aldrich), cetyltrimethyl-ammonium chloride (CTAC, 25% in H2O, Sigma-Adrich), *N*-(3-dimethylaminopropyl)-*N*-ethylcarbodiimide hydrochloride (EDC, >97%, Sigma-Adrich), *N*-hydroxysulfosuccinimide (sulfo-NHS, 98%, Sigma-Adrich), octadecyltrimethylammonium bromide (C18Br, Sigma-Adrich), propidium iodide, tetraethylorthosilicate (TEOS, >98%, Sigma-Aldrich), triethanolamine (TEA, 98%, Fluka), triisopropylbenzene (TiPB, 96%, Sigma-Adrich). Oligomer 454 [42] and Mal-PEG-GE11 [41] were synthesized as described before. siRNA and miRNA duplexes were purchased from Axolabs GmbH (Kulmbach, Germany): control RNA (sense: 5-AuGuAuuGG ccuGuAuuAGdTsdT-3, antisense: 5-CuAAuAcAGGCcAAuAcAUdTsdT-3), miR200c (sense: 5-UCCAUCAUUACCCGGCAGUAUUA-3, antisense: 5-UAAUACUGCCGGGUAAUGAUGGA-3).
