Heterogeneous molecular packing and water effects on the mechanical behaviour of silk-inspired β-sheet crystallites: A steered molecular dynamics study

Uguz C., AKDERE Ü., TAŞSEVEN Ç.

Computational Materials Science, cilt.258, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 258
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.commatsci.2025.114053
  • Dergi Adı: Computational Materials Science
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Applied Science & Technology Source, Chimica, Communication Abstracts, Compendex, Computer & Applied Sciences, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Mechanical behavior, Packing heterogeneity, Steered molecular dynamics, Water effect, β-sheet crystals
  • Yıldız Teknik Üniversitesi Adresli: Evet

Özet

Bombyx-mori silk fibroin (SF) features outstanding mechanical properties, arising from its β-sheet content. This study investigates the effect of heterogenous molecular packing and water environment on the mechanical behaviour of silk-inspired β-sheet crystallites using steered molecular dynamics (SMD) simulation technique. Two distinct antipolar antiparallel crystallite models were constructed based on experimental Silk II structures, differing intermolecular packing arrangements, instead of widely used highly ordered theoretical model of β-sheet structure. Results of pull-out simulations of six different β-chains reveal that heterogeneous molecular packing introduces location-dependent mechanical strength, which cannot be predicted based on chain region (core vs. surface) only. Water selectively weakens the surface and corner chains while either ineffective or slightly enhances the strength via hydrogen bond bridges formed prior to ultimate rupture. It also smoothens the stick–slip motion and expedites complete dissociation. Our finding provides atomistic insights into structure–mechanical relationship silk fibroin and highlight the critical role of packing heterogeneity and aqueous environment in tuning silk-based materials for biomedical and engineering applications.