Cooperative and Noncooperative Assembly of Oligopyrenotides Resolved by Atomic Force Microscopy

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• 作者：Alexander V. Rudnev ; Vladimir L. Malinovskii ; Alina L. Nussbaumer ; Artem Mishchenko ; Robert H盲ner ; Thomas Wandlowski
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：August 14, 2012
• 年：2012
• 卷：45
• 期：15
• 页码：5986-5992
• 全文大小：564K
• 年卷期：v.45,no.15(August 14, 2012)
• ISSN：1520-5835

文摘

The supramolecular assembly of amphiphilic oligopyrenotide building blocks (covalently linked heptapyrene, Py₇) is studied by atomic force microscopy (AFM) in combination with optical spectroscopy. The assembly process is triggered in a controlled manner by increasing the ionic strength of the aqueous oligomer solution. Cooperative noncovalent interactions between individual oligomeric units lead to the formation of DNA-like supramolecular polymers. We also show that the terminal attachment of a single cytidine nucleotide to the heptapyrenotide (Py₇-C) changes the association process from a cooperative (nucleation鈥揺longation) to a noncooperative (isodesmic) regime, suggesting a structure misfit between the cytidine and the pyrene units. We also demonstrate that AFM enables the identification and characterization of minute concentrations of the supramolecular products, which was not accessible by conventional optical spectroscopy.