Molecular array generation using photoresist

A method for providing an array, comprising:

• (a) irradiating a substrate comprising a layer of positive photoresist to expose a first region and not expose a second region, wherein oligonucleotide molecules attached to the substrate at their 5′ ends in the first region and in the second region are embedded in the layer of positive photoresist and comprise 3′ hydroxyl functional groups that are not protected by a protecting group;
• (b) treating the layer of positive photoresist with a developer solution to dissolve and remove the layer of positive photoresist in the first region, thereby rendering 3′ hydroxyl functionalized ends of the oligonucleotide molecules attached to the substrate in the first region available for hybridization and/or ligation, whereas 3′ hydroxyl functionalized ends of the oligonucleotide molecules attached to the substrate in the second region are protected by the layer of positive photoresist in the second region from hybridization and/or ligation;
• and
• (c) attaching an oligonucleotide comprising a barcode sequence to a 3′ hydroxyl functionalized end of an oligonucleotide molecule of the oligonucleotide molecules attached to the substrate in the first region via hybridization and/or ligation, wherein the 3′ hydroxyl functionalized ends of the oligonucleotide molecules attached to the substrate in the second region do not receive the barcode sequence,
• thereby providing, on the substrate, an array comprising different oligonucleotide molecules in the first region and the second region.