Potentiostatic deposition of DNA for scanning probe microscopy
| Autor: | J. A. DeRose, P. I. Oden, Luda S. Shlyakhtenko, Stuart Lindsay, Rodney E. Harrington, Lyubchenko YuL, Nongjian Tao |
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| Jazyk: | angličtina |
| Předmět: |
Base Sequence
Chemistry Scanning electron microscope Viscosity Molecular Sequence Data Biophysics Analytical chemistry Scanning capacitance microscopy DNA law.invention Scanning probe microscopy Adsorption Oligodeoxyribonucleotides law Microscopy Scanning Tunneling Microscopy Electrode Scanning ion-conductance microscopy Potentiometry Nucleic Acid Conformation Thermodynamics Scanning tunneling microscope Mathematics Research Article |
| Zdroj: | Biophysical Journal. (6):1570-1584 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/S0006-3495(92)81961-6 |
| Popis: | We describe a procedure for reversible adsorption of DNA onto a gold electrode maintained under potential control. The adsorbate can be imaged by scanning probe microscopy in situ. Quantitative control of a molecular adsorbate for microscopy is now possible. We found a potential window (between 0 and 180 mV versus a silver wire quasi reference) over which a gold (111) surface under phosphate buffer is positively charged, but is not covered with a dense adsorbate. When DNA is present in these conditions, molecules adsorb onto the electrode and remain stable under repeated scanning with a scanning tunneling microscope (STM). They become removed when the surface is brought to a negative charge. When operated at tunnel currents below approximately 0.4 nA, the STM yields a resolution of approximately 1 nm, which is better than can be obtained with atomic force microscopy (AFM) at present. We illustrate this procedure by imaging a series of DNA molecules made by ligating a 21 base-pair oligonucleotide. We observed the expected series of fragment lengths but small fragments are adsorbed preferentially. |
| Databáze: | OpenAIRE |
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