Protein Adsorption Enhances Energy Dissipation in Networks of Lysozyme Amyloid Fibrils

Abstract

Hydrogels of amyloid fibrils are a versatile biomaterial for tissue engineering and other biomedical applications. Their suitability for these applications has been partly ascribed to their excellent and potentially engineerable rheological properties. However, while in biomedical applications the gels have to function in compositionally complex physiological solutions, their rheological behavior is typically only characterized in simple buffers. Here we show that the viscoelastic response of networks of amyloid fibrils of the protein lysozyme in biologically relevant solutions substantially differs from the response in simple buffers. We observe enhanced energy dissipation in both cell culture medium and synovial fluid. We attribute this energy dissipation to interactions of the amyloid fibrils with other molecules in these solutions and especially to the adsorption of the abundantly present protein serum albumin. This finding provides the basis for a better understanding of the performance of amyloid hydrogels in biomedical applications.

Amyloid fibril-nanocellulose interactions and self-assembly

“…While the G 0 $ c 1:0AE0:1 CNC relationship shows the proportional increase of elasticity with CNC addition, attributed to cross-link formation and bundling, the G 0 $ c 4:0AE0:1 CNF scaling law indicates the formation of a double network of the added TO-CNFs [58][59][60]. On the other hand, the scaling of elasticity with amyloid concentration to the exponent of 2.3 ± 0.1 is in good agreement with the affine thermal model and experimental data for amyloid fibrils and other filamentous proteins [49,[53][54][55]. Finally, homogenous, almost transparent hybrid HEWL and BLG amyloid-nanocellulose gels were made using a pH-mediated self-assembly method.…”

“…As for the amyloid-CNC system scaling laws were successfully fitted and linked to the charge-dependent cross-linking between amyloids and nanocellulose. The almost identical exponent of 2.4 for the scaling law with amyloid concentration agrees well with both theory and experimental data [49,[53][54][55], describing the contribution of the amyloid fibrils to network elasticity. On the other hand, the elasticity scaling with TO-CNFs was fundamentally different to the scaling with CNCs.…”

“…amyloid Indeed, Cao et al found exponents of 2.2 for semiflexible BLG and HEWL amyloids cross-linked with NaCl, fitting the affine thermal model [49]. Instead, van Dalen et al used the non-affine floppy modes model on to describe their HEWL amyloid network elasticity, scaling with the amyloid concentration to the power of 2.4 [55].…”

Multidomain peptide hydrogel adjuvants elicit strong bias towards humoral immunity

“…These results are consistent with observed stiffening and improved energy dissipation upon the addition of several negatively charged proteins to a positively charged protein-based hydrogel made from aggregated lysozyme. 43 We conclude that including antigen does not significantly impede, and may improve, the ability of MDPs to form a shear-recovering hydrogel under the conditions tested.…”

“…In some cases, the mechanical properties of supramolecular peptide hydrogels can be sensitive to the presence of encapsulated protein. 43 To determine if that loading protein antigen into MDP hydrogels would negatively impact their physical properties, MDP gels with 0.2 mg mL −1 OVA were characterized by oscillatory rheology to determine the storage ( G ′) and loss ( G ′′) moduli and shear recovery of the hydrogels. For all gels and conditions tested, G ′ > G ′′ and G ′ was largely frequency-independent over the tested range, indicating that the materials behave as viscoelastic hydrogels over the frequency regime of 0.1–10 rad s −1 (Fig.…”