Micropatterned avidin arrays on silicon substrates via photolithography, self-assembly and bioconjugation.

Processes for micropatterning protein arrays on inorganic substrates have gained attention in the development of biosensors and clinical diagnostics. This study demonstrates a chemically selective method based on photolithographic deposition of gold patterns with the subsequent attachment of functionalized alkanethiols via molecular self-assembly. Selective capping of carboxy groups on alkanethiols by N-hydroxysuccinimide esters allowed the deposition of methoxypoly(ethylene glycol) silane as a blocking agent on unpatterned regions. Carboxylates were used to couple a form of avidin to create a microarray of protein. This microarray was successfully probed with biotinylated quantum dots. In-process characterization methods included grazing-angle Fourier-transform IR spectroscopy, ellipsometry, contact-angle goniometry, atomic-force microscopy and fluorescence microscopy.