Patent ID: 8278630

Claim:
A method for detecting features of an array, comprising: (a) providing a flow cell comprising a first interior surface and a second interior surface that are in a generally mutually facing relation, wherein the first interior surface and the second interior surface are separated by a fluid passage; (b) randomly disposing nucleic acids on the first interior surface and on the second interior surface, thereby forming an array of nucleic acid sites that is distributed on the first interior surface and on the second interior surface, wherein the nucleic acid sites are present at a density of at least 1,000 sites per square millimeter; and (c) performing a sequencing by ligation reaction, comprising: (i) introducing fluorescent oligonucleotides to the flow cell to add fluorescent tags to the nucleic acid sites; (ii) detecting the fluorescent tags at the nucleic acid sites of the array on the first interior surface at a resolution to distinguish the nucleic acid sites on the first interior surface; and (iii) repeating steps (c)(i) and (c)(ii).