Apparatus for implementing non-destructive quality control of substrates and printed biological microarrays
Apparatus implements non-destructive quality control of substrates and printed biological microarrays. A method and apparatus are provided for implementing quality control of gel-based microarrays prepared by dispensing a gel-forming composition on a solid substrate. The method utilizes the difference between the wettability properties of a supporting substrate and a gel, where the gel is hydrophilic. Condensation of vapor of a chemically inert water-soluble liquid, such as water or glycerol, on the surface of a substrate under inspection creates a layer of tiny droplets that affect both transmission and scattering of light on the surface. A pattern of condensation, characterized by spatial distribution, average size of the droplets and spacing between the droplets, reflects variation in wetting properties of the substrate. The pattern of condensation circumscribes printed microarray features to be non-destructively imaged and analyzed.
1. Apparatus for implementing non-destructive quality control of substrates for receiving microarray features of biological microarrays and for non-destructive quality control of microarrays comprising:
a microarray substrate including a substrate surface carrying a plurality of microarray elements;
a thermally insulated chamber receiving said microarray substrate; said thermally insulated chamber having an inlet port and an exhaust port;
a source of moist warm air having a temperature greater than room temperature, and the moist warm air having a dew point higher than the temperature of the substrate and a carrier gas being applied to said inlet port and transporting said moist warm air to said exhaust port creating a layer of condensate droplets of a chemically inert water-soluble liquid on said surface of said microarray substrate under inspection; said condensate droplets being densely spaced droplets having an average size substantially less than the microarray features; said layer of condensate droplets affecting both transmission and scattering of light on the surface; and
a digital image processing system illuminating said surface of said substrate under inspection; detecting an image of said illuminated surface of said substrate under inspection; and identifying a pattern of said condensate droplets on said surface of said substrate under inspection, said pattern characterized by spatial distribution, average size of the condensate droplets and spacing between the condensate droplets, reflecting variation in wetting properties of the substrate; said digital image processing system visually detecting an area indicating presence of undesirable variation of wettability and rejecting said substrate under inspection, responsive to detecting the area indicating presence of undesirable variation of wettability.
2. Apparatus for implementing non-destructive quality control as recited in claim 1 wherein said substrate surface supports a microarray of printed biological features, and said layer of condensate droplets forming multiple densely spaced droplets on the substrate surface between printed biological features and the array elements remaining clear; and wherein said digital image processing system identifies microarray quality, said microarray being visible in both transmitted and reflected light.
3. Apparatus for implementing non-destructive quality control as recited in claim 1 wherein said substrate surface supports a microarray of gel elements, where said gel is hydrophilic, and said layer of condensate droplets forming multiple densely spaced droplets on the substrate surface between array elements and the array elements remaining clear; and wherein said digital image processing system identifies array quality, said microarray being visible in both transmitted and reflected light.
4. Apparatus for implementing non-destructive quality control of printed biological microarrays comprising:
a microarray substrate including a substrate surface carrying a plurality of microarray elements;
a thermally insulated chamber receiving said microarray substrate; said thermally insulated chamber having an inlet port and an exhaust port;
a source of moist warm air having a temperature greater than room temperature, and the moist warm air having a dew point higher than the temperature of the substrate and a carrier gas being applied to said inlet port and transporting said moist warm air to said exhaust port creating a layer of condensate droplets of a chemically inert water-soluble liquid on said surface of said microarray under inspection; said condensate droplets being densely spaced droplets having an average size of at least ten times smaller than microarray features; said layer of condensate droplets affecting both transmission and scattering of light on the surface; and
a digital image processing system illuminating said microarray under inspection; detecting an image of said illuminated microarray under inspection; and identifying a pattern of said condensate droplets from said detected image of said surface of said microarray under inspection, said pattern characterized by spatial distribution, average size of the condensate droplets and spacing between the condensate droplets, reflecting variation in wetting properties of the substrate; said digital image processing system visually detecting a presence of undesirable variation of microarray features; and rejecting said microarray under inspection responsive to visually detecting the presence of undesirable variation of microarray features.