Preparation of Aluminum Oxide-Coated Glass Slides for Glycan Microarrays

In this study, we report the fabrication of aluminum oxide-coated glass (ACG) slides for the preparation of glycan microarrays. Pure aluminum (Al, 300 nm) was coated on glass slides via electron-beam vapor deposition polymerization (VDP), followed by anodization to form a thin layer (50-65 nm) of aluminum oxide (Al-oxide) on the surface. The ACG slides prepared this way provide a smooth surface for arraying sugars covalently via phosphonate formation with controlled density and spatial distance. To evaluate this array system, a mannose derivative of α-5-pentylphosphonic acid was used as a model for the optimization of covalent arraying based on the fluorescence response of the surface mannose interacting with concanavalin A (ConA) tagged with the fluorescence probe A488. The ACG slide was characterized using scanning electron microscopy, atomic force microscopy (AFM), and ellipsometry, and the sugar loading capacity, uniformity, and structural conformation were also characterized using AFM, a GenePix scanner, and a confocal microscope. This study has demonstrated that the glycan array prepared from the ACG slide is more homogeneous with better spatial control compared with the commonly used glycan array prepared from the N-hydroxysuccinimide-activated glass slide.