Abstract text (incl. figure legends and references)
Introduction: We recently showed that self-assembled fibrinogen nanofibers support the growth of fibroblasts and keratinocytes1,2 and enhance adhesion and spreading of blood platelets3. Since platelet interaction with fibrinogen nanofibers is dependent on the presence of plasma proteins3, we now want to understand how self-assembled fibrinogen nanofibers interact with various proteins involved in tissue repair.
Objectives: Hence, we studied the ability of various plasma and ECM proteins to bind to self-assembled fibrinogen nanofibers.
Methods: Fibrinogen nanofibers were assembled as previously described using planar and physisorbed fibrinogen samples2 as controls. Collagen, laminin, fibronectin, and fibrinogen were dissolved in HEPES buffer and incubated on the different samples for 4 h at 37 °C. Subsequently, the amount of bound protein was measured by UV-Vis spectroscopy of the supernatant at 280 nm and with a colorimetric bicinchoninic acid (BCA) assay.
Results: UV-Vis spectroscopy and BCA assay showed that all proteins bound to fibrinogen nanofibers to a greater extent than to planar and physisorbed fibrinogen. We attributed these differences to the 15-fold difference in surface roughness2. When the time of scaffold cross-linking in formaldehyde vapor was increased from 1 to 2 h we also found an increase in binding of all proteins independent of the surface topography. When the pH of fibrinogen solutions was raised above its IEP and below its IEP for collagen solutions, we observed increased binding to all fibrinogen substrates, which might be correlated with changes in the electrostatic interaction forces.
Conclusion: Self-assembled fibrinogen nanofibers support the binding of selected ECM and plasma proteins. Further studies are needed to characterize fully the molecular bioactivity of nanofibrous fibrinogen scaffolds.
References:
1 Suter, N. et al. Mater. Sci. Eng. C 2021
2 Joshi, A. et al. ACS Omega 2023
3 Kenny, M. et al. Adv. Healthc. Mater. 2022