Modification of Fluorophore Photophysics through Peptide-Driven Self-Assembly

Abstract

We describe the formation of self-assembling nanoscale fibrillar aggregates from a hybrid system comprising a short polypeptide conjugated to the fluorophore fluorene. The fibrils are typically unbranched, approximately 7 nm in diameter, and many microns in length. A range of techniques are used to demonstrate that the spectroscopic nature of the fluorophore is significantly altered in the fibrillar environment. Time-resolved fluorescence spectroscopy reveals changes in the guest fluorophore, consistent with energy migration and excimer formation within the fibrils. We thus demonstrate the use of self-assembling peptides to drive the assembly of a guest moiety, in which novel characteristics are observed as a consequence. We suggest that this method could be used to drive the assembly of a wide range of guests, offering the development of a variety of useful, smart nanomaterials that are able to self-assemble in a controllable and robust fashion.

Lyotropic phase behaviour of dilute, aqueous hen lysozyme amyloid fibril dispersions

“…However, occasionally such structures have been found to perform benign biological functions in living organisms, for example as a matrix material that facilitates surface-binding of Escherichia coli bacteria [2], or as a catalytic scaffold for the synthesis of melanin in human melanosomes [3]. Inspired by such potentially useful qualities, more recently, amyloid fibrils have been extensively investigated as functional materials that direct supra-molecular self-assembly [4][5][6], or serve as templates for, e.g. metal nanoparticles [7][8][9] and conjugated (poly)electrolytes [10][11][12][13][14].…”

Amyloid Fibrils – Self-Assembling Proteins

“…Enzymatic digestion of the peptide outer shell will produce silver nanowires of uniform dimensions. The formation of electroactive luminescent self-assembled nanowires from co-assembly of an amyloidogenic protein and a semiconducting oligoelectrolyte has significant implications for designing and assembling conducting nanomaterials and electroactive material (Herland et al, 2005;Channon et al, 2008). Coupled with the ability to coassemble more than one type of amyloidogenic protein within a fibril suggests endless possibilities for smart materials.…”

“…Could amyloid fibrils derived from food-based proteins be an alternative to the current material used? Based on recent research (MacPhee and Dobson, 2000;Baldwin et al, 2006;Channon et al, 2008;Gras et al, 2008) the possibility of functionalizing the fibril or fibril surface with other ingredients such as antioxidant, nutrients and flavors may be possible.…”

Cytoskeletal‐like Supramolecular Assembly and Nanoparticle‐Based Motors in a Model Protocell

“…[35] Compared with the aqueous Fmoc-TyrP (Figure 2 c), the Fmoc-Tyr hydrogel showed a characteristic hypochromicity for the absorption band at 265 nm, in contrast with the peak at 299 nm (Figure 2 d); this effect is due to superhelical stacking of the Fmoc groups in the Fmoc-Tyr hydrogel. [36,37] The corresponding change in the A 265 /A 299 intensity ratio was almost the same for both the control hydrogel and the supramolecular hydrogel vesicles ( Figure 2 c-e; 3.5:1, 3.2:1 and 3.0:1 for the aqueous Fmoc-TyrP, Fmoc-Tyr control gel, and hydrogel vesicles, respectively), indicating that self-assembly of the supramolecular array of Fmoc-modified amino acid molecules was unperturbed by confinement within the phospholipid vesicle interior. This conclusion was consistent with the presence of red-shifted bands corresponding to the amide group, emergence of an absorbance for the phenol moiety, and the disappearance of the signal for the P-O-aryl stretch in the ATR-FTIR spectra (see Figure S3 in the Supporting Information).…”