sentences:  The oligonucleotide pool is amplified and a sufficient amount of the initial library is added to the reaction so that there are numerous copies of each individual sequence to minimize the loss of potential binding sequences due to stochastic events.Before the library is introduced to target for incubation and selective retention, the sequence library must be converted to single stranded oligonucleotides to achieve structural conformations with target binding properties.Immediately prior to target introduction, the single stranded oligonucleotide library is often heated and cooled slowly to renature oligonucleotides into thermodynamically stable secondary and tertiary structures.