2. PUA molding  UV curable poly(urethane acrylate)
used instead of PDMS (poly(dimethyl siloxane))
mechanical properties of PDMS makes
it difficult to create sub 100 nm features
low elastic modulus, high compressibility
photo-cross-linkable PEG dimethacrylate
features as small as 50 nm could be created
through capillary action the PEG fills the voids of the mould
then cured through exposure to UV

4. PEG nanopillars for protein and cell adsorption studies
150 base
50 peak
500 nm spaces
nm height
adhered fibroblast
filopodia growth along nanopillar structure