Patent attributes
An example of a flow cell includes a substrate and a pattern of two different silanes on at least a portion of a surface of the substrate. A first polymer is attached to a first of the two different silanes and a second polymer is attached to a second of the two different silanes. The first and second polymers respectively include a first functional group and a second functional group of a functional group pair, the functional group pair being selected from the group consisting of an activated ester functional group and an azide functional group, a tetrazine functional group and an activated ester functional group, and a tetrazine functional group and an azide functional group. A first primer set is grafted to the first polymer and a second primer set is grafted to the second polymer. The first and second primer sets are different.