Figure 2.

a) Polysaccharide-polyplex nanofilm coating procedure of silicon nanoneedles and high-aspect ratio nanostructures. b) Confocal microscopy representative image of silicon nanoneedles coated with hyaluronate-chitosan-pDNA polyplex nanofilms. The nanofilm was stained with TAMRA (red) and pDNA-polyplexes were stained with DAPI (blue). Scale bars represent 20 μm. Separate images for each channel can be found in Figure S1, Supporting Information. c) Scanning electron microscopy (SEM) images of i) pristine nanoneedles and ii) polyplex-nanofilm coated nanoneedles. Scale bars represent 10 μm. d) Carbon, oxygen, nitrogen, sulfur, phosphorus, and silicon spectra obtained via XPS from pristine, coated (no polyplex) and polyplex-coated (4 layers) nanoneedles. e) Surface topography characterization via atomic force microscopy (AFM) for pristine, coated (no polyplex) and polyplex coated (4 layers) flat silicon substrates. Scale bars represent 2 μm.