title: A novel electrochemical method to detect theophylline utilizing silver ions captured within abasic site-incorporated duplex DNA.
abstract: We herein describe a novel and label-free electrochemical system to detect theophylline. The system was constructed by immobilizing duplex DNA containing an abasic site opposite cytosine on the gold electrode surface. In the absence of theophylline in a sample, silver ions freely bind to the empty abasic site in the duplex DNA leading to the highly elevated electrochemical signal by the redox reaction of silver ions. On the other hand, when theophylline is present, it binds to the abasic site by pseudo base pairing with the opposite cytosine nucleobase, which consequently prevents silver ions from binding to the abasic site. As a result, redox reaction of silver ions would be greatly reduced resulting in the accordingly decreased electrochemical signal. By employing this electrochemical strategy, theophylline was reliably detected at a concentration as low as 3.2 μM with the high selectivity over structurally similar substances such as caffeine and theobromine. Finally, the diagnostic capability of this method was also successfully verified by reliably detecting theophylline present in a real human serum sample with an excellent recovery ratio within 100±6%.
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Jun Ki
authors.initials: JK
authors.lastname: Ahn
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Ki Soo
authors.initials: KS
authors.lastname: Park
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Byoung Yeon
authors.initials: BY
authors.lastname: Won
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21+ Program), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea. Electronic address: hgpark@kaist.ac.kr.
authors.forename: Hyun Gyu
authors.initials: HG
authors.lastname: Park
mesh_terms: D015374:Biosensing Techniques; D003596:Cytosine / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry; D006801:Humans; D007477:Ions / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D013806:Theophylline / Q000737:chemistry / Q000302:isolation & purification*; D013941:Thymine / Q000737:chemistry
chemical_list: D007477:Ions; D012834:Silver; D006046:Gold; D003596:Cytosine; D004247:DNA; D013806:Theophylline; D013941:Thymine
keywords: Abasic sites; DNA; Electrochemical biosensor; Silver ion; Theophylline