title: Rapid and Label-Free Strategy to Isolate Aptamers for Metal Ions.
abstract: Generating aptamers that bind to specific metal ions is challenging because existing aptamer discovery methods typically require chemical labels or modifications that can alter the structure and properties of the ions. In this work, we report an aptamer discovery method that enables us to generate high-quality structure-switching aptamers (SSAs) that undergo a conformational change upon binding a metal ion target, without the requirement of labels or chemical modifications. Our method is more efficient than conventional selection methods because it enables direct measurement of target binding via fluorescence-activated cell sorting (FACS), isolating only the desired aptamers with the highest affinity. Using this strategy, we obtained a highly specific DNA SSA with ∼30-fold higher affinity than the best aptamer for Hg(2+) in the literature. We also discovered DNA aptamers that bind to Cu(2+) with excellent affinity and specificity. Both aptamers were obtained within four rounds of screening, demonstrating the efficiency of our aptamer discovery method. Given the growing availability of FACS, we believe our method offers a general strategy for discovering high-quality aptamers for other ions and small-molecule targets in an efficient and reproducible manner.
authors.affiliation: School of Biological and Medical Engineering, Hefei University of Technology , Hefei, Anhui 230009, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Qu
authors.affiliation: Materials Department, University of California at Santa Barbara , Santa Barbara, California 93111, United States.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Csordas
authors.affiliation: Aptitude Medical Systems , Santa Barbara, California 93105, United States.
authors.forename: Jinpeng
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Molecular Biology, Massachusetts General Hospital/Harvard Medical School , Boston, Massachusetts 02114, United States.
authors.forename: Seung Soo
authors.initials: SS
authors.lastname: Oh
authors.affiliation: Materials Department, University of California at Santa Barbara , Santa Barbara, California 93111, United States.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Eisenstein
authors.affiliation: Department of Electrical Engineering and Department of Radiology, Stanford University , Stanford, California 94305, United States.
authors.forename: Hyongsok Tom
authors.initials: HT
authors.lastname: Soh
mesh_terms: D052157:Aptamers, Nucleotide; D005434:Flow Cytometry; D007477:Ions; D008670:Metals; D052156:SELEX Aptamer Technique
chemical_list: D052157:Aptamers, Nucleotide; D007477:Ions; D008670:Metals
keywords: aptamers; fluorescence-activated cell sorting; metal ions; molecular screening