Length-Scale-Dependent surface roughness measurements of bioactive polymer thin films using scanning probe microscopy

Abstract

The development of implantable biomedical devices requires active biological interfaces that minimize the body’s immune response. We have identified candidate protein polymer coatings for biomedical applications and methods of processing these coatings that promote a favorable in vitro biological performance. However, the chronic implantation of biomedical devices, specifically the neural prosthetic devices developed at the University of Michigan, places additional requirements on the polymer coatings. Among these constraints are the efficient transport of neuronal signals from tissue to the device and the prevention of physical displacement of the device through tissue. To meet these potentially conflicting goals, we are developing discontinuous, porous polymer coatings that are rough at biologically-relevant length scales.In order to quantify the surface morphology of these thin polymer films, which are typically 0.02 μm to 5.0 μm thick, we employ a number of complementary techniques, including scanning probe microscopy (SPM), scanning electron microscopy (SEM), light optical microscopy (LOM), and transmission electron microscopy (TEM).