Patterned and switchable surfaces for biomaterial applications

Andrew Hook – Patterned and switchable surfaces for biomaterial applicationsmicroarray that can be used as a base substrate for additional array formation. Thearray format allows for the parallel analysis of varied polymers with theirperformance as an immobilisation matrix for DNA microarrays, however, specificanalysis of the interactions between various polymers and biomolecules is of interest.Force-distance (F-D) curves achieved by atomic force microscopy (AFM) are apowerful tool for the investigation of the adhesive, viscoelastic and stiffnessproperties of materials [310]. For this reason, F-D curves were performed on a DNAmodifiedtip and polymer array surfaces.A2.2. Materials and methodsA2.2.1. Plasma polymerisationApproximately 1 cm 2 glass samples, cleaned by sonication for 20 min in a 5%(detergent concentration) surfactant (RBS 35, Pierce USA) wash, followed withrinsing in water and drying in a laminar flowhood, were modified with an allylamineplasma polymer (ALAPP), preformed in a custom-built reactor described elsewhere[182]. In short, the plasma reactor consisted of two circular electrodes separated by125 mm in a cylindrical reactor being 350 mm high with a diameter of 170 mm.Allylamine (Aldrich, 98% purity) was used as a monomer. Polymerisation conditionsused were a frequency of 200 kHz, a power of 20 W and an initial monomer pressureof 0.188 mbar. Deposition time was 25 s.A2.2.2. Polymer array formationPoly(allylamine) (PALA) (Sigma, MW 70000), poly(acrylic acid) (PAA)(Aldrich, MW 90000), poly(ethylene imine) (PEI) (MW 70000), poly-L-lysine (PLL)D