Polymer cell culture substrates with micropatterned carbon nanotubes.

This article presents study of the interactions between cells and micropatterned carbon nanotubes on a polymer cell culture substrate. The polymer substrates with patterned carbon nanotubes were fabricated using an imprint process, whereby the nanotubes were pressed into a polymer layer at high temperature. The patterned substrates featured 28 different nanotube patterns of microscale lanes and circles, where the feature sizes ranged from 9 to 76 microm. Osteoblast-like cells were seeded on the substrates and cell alignment was quantified via fluorescent and electron microscopy. Many patterns were fabricated on each polymer substrate, allowing 28 different experiments on each cell culture substrate, which were tested over 10,000 cells. The cell response to the patterned nanotubes showed a maximum alignment to the microlane patterns of 55 +/- 6% and no significant alignment to microcircle patterns. This work enables the study of cell response to a wider range of patterns featuring both the micro and nano length scales.

Combined microscale mechanical topography and chemical patterns on polymer cell culture substrates.

This paper presents a technique to independently form mechanical topography and surface chemical patterns on polymer cell substrates, and studies the response of osteoblast cells to these surface patterns. The patterns were formed in two separate steps: hot embossing imprint lithography formed the mechanical topography and microcontact printing created the chemical pattern. The resulting substrate had surface features consisting of embossed grooves 4 microm deep and 8 microm wide spaced by 16 microm wide mesas and microcontact printed adhesive lanes 10 microm wide with spacings that ranged from 10 to 100 microm. When presented with either mechanical topography or chemical patterns alone, the cells significantly aligned to the pattern presented. When presented with mechanical topography overlaid with an orthogonal chemical pattern, the cells aligned to the mechanical topography. As the chemical pattern spacing was increased, osteoblasts remained aligned to the mechanical topography. Unlike traditional microfabrication approaches based on photolithography and wet chemistry, the patterning technique presented is compatible with a large number of biomaterials, could form patterns with features much smaller than 1 microm, and is highly scalable to large substrates.