Surface characterization of porous, biocompatible protein polymer thin films.

Genetically engineered protein polymer coatings are intended to improve the performance of implantable neural prosthetic devices. To facilitate device integration with tissue, three-dimensionally structured protein polymer films were deposited on the devices using electrostatic atomization and gas-evolution foaming. Periodic features and the length-scale dependence of the surface roughness were identified in topographic data collected using scanning probe microscopy. Using the power spectral density of surface data, the influence of process parameters on the surface roughness of protein polymer thin films was examined. Details of surface topography are known to influence biological behavior, and the method presented was capable of quantifying the evolution of surface features at biologically relevant length scales. This study provides a means for the quantitative exploration of the effects of topography on the performance of these devices and on biocompatibility in general.