Figure 5.
Phospholipid vesicle nanoarrays and SPR sensing. (a) SEM image of a nanoarray substrate viewed in cross section. The as-fabricated nanoarrays have wells with 200 nm diameter and 600 nm periodicity, but deposition of Al2O3 by ALD (light-colored layer on surface) shrinks the well diameter to approximately 80 nm. The scale bar is 1 μm. (b) Fluorescence image of a nanoarray formed with Rho-PE labeled egg PC vesicles showing high well occupancy and that nanoarray well contents can be optically resolved. The scale bar is 10 μm. (c) A SEM image of a nanowell array (32×32) milled into a gold film. The scale bar is 5 μm. (d) Magnified SEM image of a gold nanowell array. The wells are 200 nm in diameter and have 400 nm periodicity. The scale bar is 500 nm. (e) Representative transmission spectra for SPR sensing of IgMO4 binding to myelin particles in a gold nanowell array. The red curve is the negative control spectrum where SAPE does not bind to myelin, while the blue curve is the spectrum after IgMO4 binds to myelin. IgMO4 binding results in a small red-shift of the spectrum. (f) Comparison of mean spectral shifts after incubation with SAPE and IgMO4 showing a significant difference between the two cases. The error bars are standard error of the mean and * indicates a significant difference (P = 0.03) using a one-tailed Wilcoxon matched-pairs signed rank test.