Patterned and switchable surfaces for biomaterial applications

Andrew Hook – Patterned and switchable surfaces for biomaterial applicationscomplete reaction of the crosslinker. Here, the UV lamp (multiband source, 254-365nm) was held at 1 cm distance from the sample.5.3.4. SPR imagingSPR imaging was conducted using a SPRimagerII (GWC Technologies Inc.). Acollimated polychromatic polarised light source was impinged onto a gold filmsample through a prism assembly at a specific angle of incidence. The light reflectedfrom the sample passed through a narrow band-pass filter (800 nm) and was detectedby a charge coupled detector (CCD) camera, which was able to capture an image ofthe entire optical field of the chip surface. Images were analysed using V++Precision Digital Imaging System (V.4).SPR signal standardisation studies were conducted by initially forming a polymerarray onto a gold coated glass SPR chip. The surface was initially washed with 0.05M phosphate buffer at a flow rate of 3 l/s. The SPR signal for each spot was thenmeasured against the angle of incidence of the impinging light beam and an optimalangle for subsequent fixed angle SPR measurements was selected. 0.1% (v/v) ethanolin water was then injected over the array until equilibrium was reached at a flow rateof 3 l/s. Subsequently, the SPR signal for each spot was again measured against theangle of incidence of the impinging light beam. This allowed for the measurement ofthe shift in the resonance angle as a result of a change in the refractive index of thebuffer. A similar approach was taken for all SPR measurements.Biomolecular adsorption experiments were conducted by priming the polymermicroarray initially in 0.05 M phosphate buffer at pH 7.4. Once a stable backgroundwas reached the SPR signal for each spot was measured against the angle ofincidence of the impinging light beam before 10 g/ml, 5 g/ml, 2 g/ml or 1 g/ml5-165