array of small cylinders using for example a mask aligner karl suss ma 6 the exposure time is calculated to give an exposure energy of 75 mj cm 2 at a wavelength of 365 nm the exposed areas of the photoresist are then crosslinked by heating the wafer on a hotplate at 65 u00b0 c for about 1 minute and then at 95 u00b0 c for about 1 minute finally the unexposed areas of both photoresist layers are then dissolved away by immersing the wafer in solvent su 8 developer microchem newton mass for about 9 minutes with continuous gentle agitation the completed wafer is then rinsed with for example isopropyl alcohol and dried in a stream of nitrogen profilometry measurements and evaluation by scanning electron microscopy can be used to verify that the desired surface pattern has been produced under the methods of this invention enhanced differentiation of cells into bone or bone like cells is seen specifically experiments were run using the pva h of this invention in multiple forms this description references fig3 5 for clarity as shown in fig3 there were seven conformations of the surface topography taught by this invention used in this experiment u2014 one being smooth hydrogel specifically conformation is described using a two number nomenclature system such as pva h 10 2 pva h 10 2 refers first to the size of the large pore on the surface as described above the large pore can exist in a complex structure resembling a snowflake the number 10 in the first.