Enhancing the Mechanical Properties of Guanosine-Based Supramolecular Hydrogels with Guanosine-Containing Polymers

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• 作者：Amanda E. Way ; Angie B. Korpusik ; Taylor B. Dorsey ; Lauren E. Buerkle ; Horst A. von Recum ; Stuart J. Rowan
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：March 11, 2014
• 年：2014
• 卷：47
• 期：5
• 页码：1810-1818
• 全文大小：548K
• 年卷期：v.47,no.5(March 11, 2014)
• ISSN：1520-5835

文摘

We demonstrate that multivalent, polymeric 8-methoxyguanosine derivatives based on poly(dimethylacrylamide) can enhance the mechanical properties of the low molecular weight hydrogelator 8-methoxy-2鈥?3鈥?5鈥?tri-O-acetylguanosine at biologically relevant salt concentrations. It is proposed that these nongelling polymeric derivatives, under the conditions studied, can result in a significant enhancement of these supramolecular gels (e.g., for gels containing 1 wt % gelator G鈥?can be increased from ca. 2000 Pa with no additive to 80鈥?00 Pa) by acting as supramolecular cross-linking units. Two competing mechanisms appear to play a role in these cogels. At low polymer concentrations the guanosine-containing polymers tend to act more as solubilizing agents for the gelator, thus weakening the gels, while at high guanosine-containing polymer concentrations the gels show a marked enhancement in mechanical properties consistent with them acting as supramolecular cross-linking agents. As such, the thermomechanical properties of these cogels depend on both the polymer:low molecular weight gelator ratio and the number of 8-methoxyguanosine repeat units present in the polymer additive. Thus, these polymeric guanosine-based additives impart the ability to tailor both the modulus and shear sensitivity of the gels. For example, cogels with a modulus ranging between ca. 95 and 80鈥?00 Pa can be obtained through judicious selection of the type and amount of polymer additive.