Hydrogelation and self-assembly of Fmoc-tripeptides: unexpected influence of sequence on self-assembled fibril structure, and hydrogel modulus and anisotropy

DOI: 10.1021/la903678e

Authors: G. Cheng (University of Reading) , V. Castelletto (University of Reading) , C. M. Moulton (University of Reading) , G. E. Newby (University of Reading) , I. W. Hamley (University of Reading; Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Langmuir , VOL 26 (7) , PAGES 4990-4998

State: Published (Approved)
Published: January 2010

Abstract: The self-assembly and hydrogelation properties of two Fmoc-tripeptides [Fmoc = N-(fluorenyl-9-methoxycarbonyl)] are investigated, in borate buffer and other basic solutions. A remarkable difference in self-assembly properties is observed comparing Fmoc-VLK(Boc) with Fmoc-K(Boc)LV, both containing K protected by N-epsilon-tert-butyloxycarbonate (Boc). In borate buffer, the former peptide forms highly anisotropic fibrils which show local alignment, and the hydrogels show flow-aligning properties. In contrast, Fmoc-K(Boc)LV forms highly branched fibrils that produce isotropic hydrogels with a much higher modulus (G' > 10(4) Pa), and lower concentration for hydrogel formation. The distinct self-assembled structures are ascribed to conformational differences, as revealed by secondary structure probes (CD, FTIR, Raman spectroscopy) and X-ray diffraction. Fmoc-VLK(Boc) forms well-defined beta-sheets with a cross-beta X-ray diffraction pattern, whereas Fmoc-KLV(Boc) forms unoriented assemblies with multiple stacked sheets. Interchange of the K and V residues when inverting the tripeptide sequence thus leads to substantial differences in self-assembled structures, suggesting a promising approach to control hydrogel properties.

Subject Areas: Chemistry, Materials


Instruments: I22-Small angle scattering & Diffraction

Added On: 14/04/2010 14:02

Discipline Tags:

Biomaterials Chemistry Materials Science Organic Chemistry

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)