Surface nanoscale imaging of collagen thin films by Atomic Force Microscopy

Collagen, the most abundant protein in mammals, due to its unique properties is widely used as biomaterial, scaffold and culture substrate for cell and tissue regeneration studies. Since the majority of biological reactions occur on surfaces and structures at the nanoscale level it is of great importance to image the nanostructural surface of collagen based materials. The aim of this paper was to characterize, with Atomic Force Microscopy (AFM), collagen thin films formed on different substrates (glass, mica, polystyrene latex particle surfaces) and correlate their morphology with the used substrates, formation methodologies (spin coating, hydrodynamic flow) and original collagen solution. The results demonstrated that, by altering a number of parameters, it was possible to control the formation of collagen nanostructured films consisting of naturally occurring fibrils. The spin coating procedure enabled the formation of films with random oriented fibrils, while substrates influenced the fibril packing and surface roughness. The hydrodynamic flow was used for guiding fibril major orientation, while adsorption time, rinsing with buffer and solution concentration influenced the fibril orientation. The clarification of the contribution that different parameters had on thin film formation will enable the design and control of collagen nanobiomaterials with pre-determined characteristics.