Micropatterning of inorganic precipitations in hydrogels with soft lithography

This paper presents two convenient soft-lithographic techniques (membrane transfer and microfluidic deposition) for the generation of micropatterns of inorganic precipitations in hydrogel plates. Both techniques use polydimethylsiloxane (PDMS) as the prime material for patterning; they are complementary to each other for the formation of different types of patterns that have a short or long x/y ratio. All created patterns are half-embedded in the hydrogel substrate to give a topographically flat surface. Three inorganic salts (calcium phosphate, barium sulfate and barium carbonate) are used as model for the demonstration of the patterning process.