Flow cells

A method, comprising:

• applying a first functionalized layer on a substrate;
• attaching a first primer set to the first functionalized layer by involves grafting an un-cleavable first primer and a cleavable second primer to the first functionalized layer after its application;
• patterning the first functionalized layer, thereby forming a first functionalized region covered by a photoresist;
• applying a second functionalized layer on the photoresist and portions of the substrate;
• attaching a second primer set to the second functionalized layer by grafting a cleavable first primer and an un-cleavable second primer to the second functionalized layer after its application;
• lifting off the photoresist and any of the second functionalized layer thereon;
• and
• removing a portion of the second functionalized layer, thereby forming a second functionalized region adjacent to the first functionalized region.

A method, comprising:

• applying a first functionalized layer on a substrate;
• patterning the first functionalized layer, thereby forming a first functionalized region covered by a photoresist;
• applying a second functionalized layer on the photoresist and portions of the substrate;
• lifting off the photoresist and any of the second functionalized layer thereon;
• removing a portion of the second functionalized layer, thereby forming a second functionalized region adjacent to the first functionalized region;
• depositing, respectively, a first self-assembled monolayer on the first functionalized region and a second self-assembled monolayer on the second functionalized region;
• attaching a first primer set to the first self-assembled monolayer by grafting an un-cleavable first primer and a cleavable second primer to the first self-assembled monolayer;
• and
• attaching a second primer set to the second self-assembled monolayer by grafting a cleavable first primer and an un-cleavable second primer to the second self-assembled monolayer.