Patterned and switchable surfaces for biomaterial applications

Andrew Hook – Patterned and switchable surfaces for biomaterial applicationsIn order to further optimise the formation of PEI spots, the approach speed anddwell time of the pin to the surface where altered. The PEI spots formed as a result ofaltering these parameters are shown as Figure 4.2B. Interestingly, altering dwell timeappeared to have little effect on the size or morphology of spots, however, increasingthe approach speed from 5 to 20 mm/s was observed to decrease the spot diameterfrom 580 µm to 490 µm and also decreased the spot variability, presumably byminimising the formation of the polymer rim. Thus, an approach speed of 20 mm/sand a dwell time of 10 ms were selected for subsequent PEI printing.4.3.2. Polymer microarray formationInitially, a low fouling polymer film was formed on a clean glass slide. Plasmapolymerisation [38] using allylamine as a monomer was used to deposit a thin filmdisplaying amine functional groups, which were used to subsequently graft aldehydeterminated PEG chains by reductive amination under cloud point conditions [67].Plasma polymerisation was used here as it is able to produce a pin-hole free, welladherent film on almost any base substrate, allowing this approach to readily beadapted to almost any material of choice.4-139