title: Stabilisation by freeze-drying of cationically modified silica nanoparticles for gene delivery.
abstract: Core shell silica particles with a hydrodynamic diameter of 28nm, an IEP of 7.1 and a zeta potential of +35mV at pH 4.0 were synthesised. The role of freeze-drying for the conservation of zwitterionic nanoparticles and the usefulness of different lyoprotective agents (LPA) for the minimisation of particle aggregation were studied. The activity of the nanoparticles was measured as DNA-binding capacity and transfection efficiency in Cos-1 cells before and after lyophilisation. It was found that massive aggregation occurred in the absence of LPA. Of the various LPAs screened in the present investigations, trehalose and glycerol were found to be well suited for conservation of cationically modified silica nanoparticles with simultaneous preservation of their DNA-binding and transfection activity in Cos-1 cells.
authors.affiliation: Department of Biopharmaceutics and Pharmaceutical Technology, Saarland University, 66123 Saarbrücken, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Sameti
authors.forename: G
authors.initials: G
authors.lastname: Bohr
authors.forename: M N V
authors.initials: MN
authors.lastname: Ravi Kumar
authors.forename: C
authors.initials: C
authors.lastname: Kneuer
authors.forename: U
authors.initials: U
authors.lastname: Bakowsky
authors.forename: M
authors.initials: M
authors.lastname: Nacken
authors.forename: H
authors.initials: H
authors.lastname: Schmidt
authors.forename: C-M
authors.initials: CM
authors.lastname: Lehr
mesh_terms: D000818:Animals; D019556:COS Cells; D002412:Cations / Q000008:administration & dosage / Q000737:chemistry; D002522:Chlorocebus aethiops; D016503:Drug Delivery Systems / Q000379:methods*; D004355:Drug Stability; D005612:Freeze Drying / Q000379:methods; D015316:Genetic Therapy / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000008:administration & dosage / Q000737:chemistry*
chemical_list: D002412:Cations; D012822:Silicon Dioxide