This research describes a novel and cost-effective approach of micro-patterning hydrogels using a sacrificial breath figure template. The breath figure technique (based on a water templating mechanism) can produce a mono-dispersed porous polymer film through the evaporation of a polymer solution under constant humid conditions. We hypothesized that if we used an aerosol mist carrying cargo instead of humid air, we could place the cargo specifically in the pores of the breath figures. We synthesized breath figures by casting polymer films under humid aerosol mists containing silica nanoparticles, magnetic nanoparticles and chitosan. These particles stayed in the condensed water droplets and as the droplets evaporated, they assembled only inside the pores of the breath figures.  For templating, the precursor solution of the hydrogel including hydroxyethylmethacrylate(HEMA)  was cast on top of the breath figures and polymerized. Subsequent dissolution of the template in an organic solvent exposed the reverse template on the pHEMA hydrogel surface. The resultant micro-patterned bead-like surface structures were of the order of the breath figure pore diameter. The versatility of the breath figure template was further explored with the incorporation of iron nanoparticles to make magnetically responsive polymer films. Through the casting of the hydrogel precursors onto the iron-filled breath figures, the iron-nanoparticles were selectively embedded on the patterned PHEMA surface. This newly developed breath figure based templating approach is simple to perform with a high fidelity over a large area of the substrate. This technique applied to hydrogels and biopolymers can help develop effective and attractive biomaterials for cell and protein micro-patterning substrates, tissue engineering, cell-surface interaction studies and biosensors.

Novel aerosol based technique of spatially ordered surface nanodeposition on �breath figure� templates

248th National Meeting (2014)

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