Editing Silica Nanoparticles (section)

=== protocol 1  ===

Silicalite-1 nanocrystals with a mean approximate size of 55 nm can be synthesized from a clear solution that is composed of 9 TPAOH: 0.16 NaOH: 25 Si: 495 H2O: 100 EtOH, <br> 

TPAOH: tetrapropylammonium hydroxide.&nbsp; <br> 

The clear solution is refluxed at 60 ◦ C for 240 h, washed and centrifuged.<br>To functionalize the silicalite nanoparticles, samples (55 nm silicalite calcined at 500 ◦ C in air)&nbsp; are mixed with 3-aminopropyltriethoxysilane (APTES) in 60 ml of toluene in a round-bottom flask.<br>The sample is heated in an oil bath for 4 h at 120 ◦ C. <br> 

The resulting solution is filtered to separate the functionalized nanoparticles<br> 

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Transfection 

Amine functionalized silicalite nanoparticles and unfunctionalized silicalite nanoparticles were prepared in individual batches of<br>0 . 01 mg ml − 1 in purified and 0 . 2 μ m filtered water. 

Plasmid DNA&nbsp; is&nbsp; first mixed with PEI (high molecular weight, water free; Sigma Aldrich, St Louis, MO) at an N:P ratio of 5:1, briefly vortexed and allowed to sit for 25 min at<br>room temperature. After 25 min, the PEI–pDNA polyplexes (1 μ g pDNA) or pDNA (1 μ g) is incubated with 20 μ l of the silicalite nanoparticle solution for another 8 min. Finally, the<br>silicalite nanoparticles and/or polyplexes/pDNA are added to the cells in Opti-MEM transfection medium (serum-free) and incubated for 4 h at 37 ◦ C. This is followed by incubation in<br>serum containing medium for 44 h.<br> 

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