title: Electrochemical DNA analysis with a supramolecular assembly of naphthalene diimide, ferrocene, and β-cyclodextrin.
abstract: Naphthalene diimide 1 bearing ferrocene and β-cyclodextrin (β-CD) was prepared. Its half-wave potential at 420 mV shifted 40-50 mV upon addition of an excess of adamantylamine, suggesting that the ferrocene of 1 is included in the cavity of β-CD intramolecularly to form a pseudocyclic structure. This unique architecture is retained even where 1 is bound to calf thymus DNA to give rise to a catenane-like structure. Morphology of the DNA complex with 1 was further explored by atomic force microscopy to reveal that the DNA strand tends to bend as the amount of 1 on it increases. Presumably, intermolecular, yet intrastrand, inclusion of ferrocene into β-CD is responsible for this phenomenon. The resulting globular structure reverted partially by the addition of adamantylamine. At a low ratio of 1 to DNA, a novel reduction peak appeared at 320 mV in the differential pulse voltammograms of 1 at the expense of the 420 mV peak. The peak current of the former was proportional to the DNA concentration, thereby enabling quantitation of DNA in a signal-on way. Likewise, a polymerase chain reaction (PCR) product of 754 bp was analyzed successfully with a detection limit of 13 nM.
authors.affiliation: Department of Applied Chemistry, Kyushu Institute of Technology, Sensui-cho 1-1, Tobata-ku, Kitakyushu-shi, Fukuoka 804-8550, Japan.
authors.forename: Sadayoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Shinobu
authors.initials: S
authors.lastname: Sato
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ohtsuka
authors.forename: Shigeori
authors.initials: S
authors.lastname: Takenaka
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002417:Cattle; D004247:DNA / Q000032:analysis*; D055664:Electrochemical Techniques; D005296:Ferrous Compounds / Q000737:chemistry*; D007094:Imides / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D000075163:Metallocenes; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D007094:Imides; D046911:Macromolecular Substances; D000075163:Metallocenes; D009281:Naphthalenes; D047392:beta-Cyclodextrins; C542131:naphthalenediimide; D004247:DNA; C427203:calf thymus DNA; C031215:betadex; C004998:ferrocene