title: Magnetic Core-Shell Silica Nanoparticles with Large Radial Mesopores for siRNA Delivery.
abstract: A novel type of magnetic core-shell silica nanoparticles is developed for small interfering RNA (siRNA) delivery. These nanoparticles are fabricated by coating super-paramagnetic magnetite nanocrystal clusters with radial large-pore mesoporous silica. The amine functionalized nanoparticles have small particle sizes around 150 nm, large radial mesopores of 12 nm, large surface area of 411 m(2) g(-1) , high pore volume of 1.13 cm(3) g(-1) and magnetization of 25 emu g(-1) . Thus, these nanoparticles possess both high loading capacity of siRNA (2 wt%) and strong magnetic response under an external magnetic field. An acid-liable coating composed of tannic acid can further protect the siRNA loaded in these nanoparticles. The coating also increases the dispersion stability of the siRNA-loaded carrier and can serve as a pH-responsive releasing switch. Using the magnetic silica nanoparticles with tannic acid coating as carriers, functional siRNA has been successfully delivered into the cytoplasm of human osteosarcoma cancer cells in vitro. The delivery is significantly enhanced with the aid of the external magnetic field.
authors.affiliation: School of Chemical Engineering, The University of Adelaide, SA, 5005, Australia.
authors.forename: Lin
authors.initials: L
authors.lastname: Xiong
authors.affiliation: School of Chemical Engineering, The University of Adelaide, SA, 5005, Australia.
authors.forename: Jingxu
authors.initials: J
authors.lastname: Bi
authors.affiliation: Centre for Nano Scale Science and Technology, School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, SA, 5042, Australia.
authors.forename: Youhong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: School of Chemical Engineering, The University of Adelaide, SA, 5005, Australia. s.qiao@adelaide.edu.au.
authors.forename: Shi-Zhang
authors.initials: SZ
authors.lastname: Qiao
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D002417:Cattle; D016923:Cell Death; D045744:Cell Line, Tumor; D018014:Gene Transfer Techniques; D006801:Humans; D057446:Hydrodynamics; D060328:Magnetic Phenomena; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D016062:Porosity; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D012822:Silicon Dioxide / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D034741:RNA, Small Interfering; D012822:Silicon Dioxide
keywords: gene delivery; magnetic nanoparticles; mesoporous silica; siRNA; tannic acid