Paper
The influence of side-chain halogenation on the self-assembly and hydrogelation of Fmoc-phenylalanine derivatives
Published Jul 6, 2010 · DOI · D. Ryan, Samuel B. Anderson, Bradley L. Nilsson
Soft Matter
144
Citations
0
Influential Citations
Abstract
Fmoc-protected aromatic amino acids, including Fmoc-phenylalanine (Fmoc-Phe), Fmoc-tyrosine (Fmoc-Tyr), and Fmoc-pentafluorophenylalanine (Fmoc-F5-Phe), have been shown to undergo efficient self-assembly and to promote hydrogelation in aqueous solvents. In order to probe the electronic and steric role of the benzyl side-chain in hydrophobic and π–π interactions during self-assembly, the hydrogelation behavior of monohalogenated (F, Cl, Br) Fmoc-Phe side-chain derivatives was assessed. Incorporation of single halogen substituents on the aromatic side-chain of Fmoc-Phe dramatically enhances the efficient self-assembly of these amino acid derivatives (relative to Fmoc-Phe) into amyloid-like fibrils that promote hydrogelation in aqueous solvents. The position of halogen substitution (ortho, meta, para) and the halogen itself (F, Cl, Br) exert a strong influence on the self-assembly rate and on the bulk rheological properties of the resultant hydrogel. These results demonstrate that minimal atomic substitutions can be used to tune self-assembly and gelation of small molecule hydrogelators.
Single halogen substitutions on the aromatic side-chain of Fmoc-phenylalanine significantly enhance the efficient self-assembly and hydrogelation of these amino acid derivatives in aqueous solvents.
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