MEMS Seminar: Identifying DNA-base Ligands for Material Targets
Wednesday, September 21, 2016
12:00 pm - 1:00 pm
Fitzpatrick Center Schiciano Auditorium Side A
Professor Valeria Milam
Oligonucleotide aptamers are single-stranded sequences that exhibit high affinity and specificity for a particular non-nucleotide target including, but not limited to small molecules, proteins, and even whole cells. Aptamers are conventionally identified using a multi-round screening approach called "Systematic Evolution of Ligands by Exponential Enrichment" (SELEX) in which a pool of approximately 109 random candidate sequences is continuously enriched with amplified copies of "winning" sequences or adsorbates from prior selection rounds. While SELEX has revolutionized the discovery of numerous DNA and RNA-based aptamers for a variety of targets and dominated the field for over two decades as a screening approach, we have developed a non-SELEX screening approach to identify single-stranded DNA aptamers for gold substrates. One of the key differences in our competition-based screening approach is the elimination of intermittent, time-intensive elution and amplification steps of random sequences that (1) can introduce undesirable side products (e.g. partially elongated duplexes) into the candidate pool and (2) bias the candidate pool towards early winners that may simply outnumber higher affinity aptamer candidates introduced at later selection rounds.