Patterned and switchable surfaces for biomaterial applications

CHAPTER 5.SURFACE PLASMON RESONANCE IMAGINGOF POLYMER MICROARRAYS5.55.1. IntroductionPolymer microarrays are an emerging key enabling technology for theidentification and development of new polymer materials for specific biomaterialapplications. Typically, a polymer microarray consists of an array of differentpolymers with varied properties in order to assess the biological response, includingcell attachment, proliferation or differentiation in response to a particular polymerchemistry or topography [143, 145, 218]. In one approach to creating a polymermicroarray, different ratios of 24 different monomers were arrayed in the presence ofan initiator on an epoxy coated glass substrate [145]. UV irradiation was used toinitiate the in situ polymerisation of polymer material to form rigid, cross-linkedpolymer spots. Polymer-cell interactions were assessed on this array [219, 230].However, this technique is limited to the formation of highly crosslinked polymernetworks, the structure of which may be difficult to characterise and replicate at alarger scale. Polymers arrays may also be formed by arraying pre-fabricatedpolymers to a substrate surface by a method such as robotic contact printing [143,144], allowing for the analysis of polymer materials fabricated by means of advancedpolymerisation techniques, such as atom transfer radical polymerisation or radicaladdition-fragmentation chain transfer polymerisation [231, 232]. Copolymersincluding block-copolymers are also available for printing, further increasing thecombinatorial space. Moreover, the polymers can be characterised extensively byconventional techniques before being arrayed. An array of 120 polyurethanes formed5-155