title: Optimizing Pin-Printed and Hydrosilylated Microarray Spot Density on Porous Silicon Platforms.
abstract: Microarrays of spatially isolated chemistries on planar surfaces are powerful tools. An important factor in microarray technology is the density of chemically unique spots that can be formed per unit area. In this paper, we use contact pin-printing and evaluate how to decrease contact pin-printed spot diameters on porous silicon (pSi) platforms. Using hydrosilylation chemistry to covalently attach chemistries to the pSi surface, the variables studied included pSi porosity and surface polarity, active agent viscosity, and pin diameter. The spot characteristics were assessed by Fourier transform infrared spectroscopy (FT-IR) microscopy and X-ray photoelectron spectroscopy (XPS). Spot size decreased as pSi porosity increased in accordance with molecular kinetic theory and Darcy's law of imbibition. Increasing active agent viscosity and pin diameter (volume of printed agent) led to larger spot diameters in accordance with molecular kinetic theory and Darcy's law. Oxidizing the pSi with H2O2 increased the surface polarity but had no detectable impact on the spot size. This is consistent with formation of an oxide layer atop an unoxidized pSi sublayer.
authors.affiliation: Department of Chemistry, Natural Sciences Complex, SUNY-Buffalo , Buffalo, New York 14260-3000, United States.
authors.forename: Dustin T
authors.initials: DT
authors.lastname: McCall
authors.affiliation: Department of Chemistry, Natural Sciences Complex, SUNY-Buffalo , Buffalo, New York 14260-3000, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Bausch + Lomb Incorporated, 1400 Goodman St. N., Rochester, New York 14609, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hook
authors.affiliation: Department of Chemistry, Natural Sciences Complex, SUNY-Buffalo , Buffalo, New York 14260-3000, United States.
authors.forename: Frank V
authors.initials: FV
authors.lastname: Bright