Salt-driven fibrinogen self-assembly into nanofibers and their biofunctionality

Abstract

Fibrinogen self-assembly plays a critical role in tissue engineering and wound healing. While various methods generate fibrin-like networks, salt-induced fibrinogen self-assembly has gained attention due to its efficiency and solvent-free nature. However, the underlying mechanism remains unclear. This thesis investigates fibrinogen-salt interactions to develop reproducible nanofiber scaffolds for biomedical applications. The study explores how different salts influence fibrinogen self-assembly in vitro. Initial findings show that salts in non-denaturing buffers are crucial for fiber formation. Further analysis examines the effects of divalent (Ca²⁺, Mg²⁺, Zn²⁺, Cu²⁺) and monovalent (Na⁺, K⁺, NH₄⁺) salts. Contrary to expectations, divalent ions, essential in clot formation, did not induce fibrinogen fiber formation, instead producing smooth layers. In contrast, monovalent salts in phosphate-buffered saline (PBS) triggered fibrinogen self-assembly after drying. To understand this effect, different monovalent cation-anion combinations were tested. Results revealed a direct correlation between salt composition and fibrinogen morphology, with kosmotropic cations (e.g., Na⁺) and kosmotropic anions (e.g., H₂PO₄⁻) being most effective. These findings align with Hofmeister effects, suggesting that specific ion binding and hydration shell modulation drive fibrillogenesis. Additionally, the study examines fibrinogen’s influence on sodium chloride crystal morphology, revealing a reciprocal interaction between proteins and salts. The final analysis assesses the biocompatibility of salt-induced fibrinogen nanofibers, showing increased platelet activation on fibrous surfaces. In conclusion, this research elucidates the role of salts in fibrinogen self-assembly, offering insights into ion-driven protein structuring. These findings provide insights into controlled fibrinogen nanofiber fabrication, enhancing biomaterial applications in tissue engineering and wound healing.