Patterned and switchable surfaces for biomaterial applications

Andrew Hook – Patterned and switchable surfaces for biomaterial applications(Sigma, MW 70000) and polyvinylpyrrolidone (PVP) (Fluka, MW 380000) werespotted onto ALAPP coated glass. Before spotting polymer samples were prepared to4, 2, 1, 0.5, 0.25, 0.1 and 0 mg/ml solutions in ultra pure water. 1 mg/ml N-succinimydl 5-azido-2-nitrobenzoate (Fluka) was also preadded and polymerphenylazidesolutions were incubated at 25 °C for 10 min before array formation.Spotting was conducted using a BioOdyssey Calligrapher MiniArrayer (Bio-Rad)using a 375 m diameter solid pin (ArrayIt). Spotting was conducted at a humidity of65% and at a temperature of 25 °C. The approach speed of the pin and the dwell timeof the pin in contact with the surface were set to 20 mm/s and 15 ms respectively. Allspots formed were reprinted once directly after initial spot formation to minimisevariation in spot formation. All spotting and solution preparation was conducted inthe dark. After array formation samples were exposed to UV for 10 mins. Arrayswere then imaged using a GenePix 4000A microarray scanner.A2.2.3. Polymer spin coatingAs controls, polymer samples of PALA, PAA, PEI, PLL and PVP were preparedon bare silicon by spin coating. Highly doped, p++ silicon (Virginia semiconductors,Inc.) were cut into 1 cm 2 pieces and washed by sonication for 20 min in a 5%(detergent concentration) surfactant wash. Surfaces were then dried in a laminarflowhood. Spin coating was conducted on a WS-400B-6NPP/LITE Spin coater(Laurell Technologies). 166 l of 10 mg/ml polymer solution (in water) was pipettedonto the sample such that the entire surface was covered. The sample was then spunat 3000 rpm for 10 s. After this an additional 166 l was added and the sample wasspun again for another 10 s. A further 166 l of polymer solution was added and thesample was spun for 30 s.E