Regardless of the library type, DEL selection involves the following general steps: target-library incubation, unbound molecule removal, and bound molecule recovery. Each step is of great importance in achieving potential hits. HitGen provides various DEL selection options involving different types of libraries, and each type of selection follows distinct procedures. Next-Generation Sequencing (NGS) is utilized for the sequencing process. In order to achieve high data usage efficiency, a certain range of copy number in each sample is necessary. We usually need to decide where we should stop the multi-round selection by monitoring copy number of the elution with Quantitative Real-time PCR (qPCR). A classical DEL selection scheme is shown below, please read more for Covalent DEL selection, protein degrader DEL selection, and Fragment DEL selection. 

In most cases, DEL selection at HitGen is performed with automated sample purification system (KingFisher Due prime and KingFisher Flex). For detailed selection automation, please refer to a well written paper of DEL selection using Kingfisher: Nat Protoc. 2016 Apr;11(4):764-80.