Nanostructured surfaces for anti-biofouling/anti-microbial applications

Recent nanotechnology revolutions have cast increased challenges to biotechnology including bio-adhesion of cells. Surface topography and chemistry tailored by the nanotechnology exert significant effects on such applications so that it is necessary to understand how cells migrate and adhere on three-dimensional micro- and nanostructures. However, the effects of the surface topography and chemistry on cell adhesions have not been studied systematically and interactively yet mostly due to the inability to create well-controlled nanostructures over a relatively large surface area. In this paper, we report on the bio-adhesions of varying cell types on well-ordered (post and grate patterns), dense-array (230 nm in pattern periodicity), and sharp-tip (less than 10 nm in tip radius) nanostructures with varying three-dimensionalities (50- 500 nm in structural height). Significantly lower cell proliferation and smaller cell size were measured on tall nanostructures. On a grate pattern, significant cell elongation and alignment along the grate pattern were observed. On tall nanostructures, it was shown that cells were levitated by sharp tips and easily peeled off, suggesting that cell adherence to the tall and sharp-tip nanostructures was relatively weak. The control of cell growth and adherence by the nanoscale surface topographies can benefit the micro- and nanotechnogies-based materials, devices, and systems, such as for anti-biofouling and anti-microbial surfaces. The obtained knowledge by this investigation will also be useful to deal with engineering problems associated with the contact with biological substances such as biomaterials and biosensors.