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Volumn 38, Issue 7, 1999, Pages 941-945

Long-range electron transfer through DNA films

Author keywords

Biosensors; Cyclic voltammetry; DNA structures; Electron transfer; Monolayers; Thin films

Indexed keywords

DAUNORUBICIN; DNA;

EID: 0033119805     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/(SICI)1521-3773(19990401)38:7<941::AID-ANIE941>3.0.CO;2-7     Document Type: Article
Times cited : (418)

References (65)
  • 27
    • 33747530521 scopus 로고    scopus 로고
    • note
    • [9] were carried out under electrochemical control, and revealed that the DNA films undergo a potential-dependent change in structure. At open circuit, the monolayer film height is 45(3) Å. Based on the anisotropic dimensions of the 15-base-pair duplexes (20 Å in diameter versus 60 Å in length), this thickness indicates that the helical axis is oriented at about 45° from the gold surface. At applied voltages negative of the potential of zero charge, film thicknesses of about 60 Å are observed; more positive potentials cause a drop in the film height to a limiting value of 20 Å at low surface coverages.
  • 35
    • 33747522693 scopus 로고    scopus 로고
    • note
    • -2. The Γ value for DM appears to exceed slightly the theoretical Γ value for DNA, and likely results from electrode surface roughness.
  • 36
    • 33747530214 scopus 로고    scopus 로고
    • note
    • 4- (2 mM) was monitored. This negatively charged ion is repelled from the surface of the modified electrode by the polyanionic DNA, and exhibits essentially no response when !he surface is well covered. While not a direct measure of surface coverage, this technique allows the convenient assay of individual electrodes for adequate modification. As the electrode-modification procedure did not always result in uniform surface coverages for the DM-modified duplexes, only electrodes that appeared well covered using both the integrated current of the DM reduction and the ferrocyanide test were studied.
  • 37
    • 33747579999 scopus 로고    scopus 로고
    • note
    • Based on molecular modeling, if DM is bound at the end of the duplex closest to the electrode (Figure 3a), the through-helix DM-electrode separation is greater than 10 Å; if the intercalator is cross-linked to the end of the duplex farthest from the electrode, the DM-electrode separation is greater than 35 Å (Figure 3b).
  • 48
    • 33747521021 scopus 로고    scopus 로고
    • note
    • The coulometry of DM at electrodes modified with CA-containing duplexes varied to some degree as a function of the surface coverage. At high surface coverages (as determined by the ferrocyanide assay), essentially no signal was observed with the mismatched duplexes. However, at more moderate surface coverages, small signals corresponding to the reduction of DM were found. These typically did not exceed 30% of the signals found for the TA duplexes. The morphology of partial DNA monolayers is unknown.
  • 49
    • 33747551053 scopus 로고    scopus 로고
    • note
    • The AFM measurements revealed monolayer thicknesses of about 40 Å at open circuit for both CA- and TA-containing duplexes; moreover, the oxidation of ferrocyanide was similarly attenuated at both surfaces. Expected masses for DM-cross-linked DNA duplexes (accounting for the one-base change) were measured by mass spectrometry, and spectrophotometric assays revealed that the extent of cross-linking was identical in both fully paired and mismatched sequences.
  • 64
    • 33747555337 scopus 로고    scopus 로고
    • note
    • 2 (pH7), thermal denaturation studies of 5 μM duplexes (monitored by absorbance at 260 nm) revealed melting temperatures of 48 and 50°C for the native and DM-cross-linked duplexes, respectively. A similar melting profile was obtained by monitoring hypochromicity at 482 nm for the DM duplex.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.