Interfacial Assembly Reprograms Defect-Mediated Bending Mechanics in Rigid Biogenic Nanofibrils

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Rigid biogenic nanofibrils' mechanics are typically linked to structure, crystallinity, and alignment.
• The influence of sparse geometric defects on fibril mechanics is not well understood.

Purpose of the Study:

• To investigate the role of intrinsic kink defects in the mechanics of Hyphantria cunea silk nanofibrils.
• To explore how interfacial assembly of silk fibroin affects nanofibril bending behavior.

Main Methods:

• Analysis of kink defects in Hyphantria cunea silk nanofibrils.
• Interfacial assembly of Bombyx mori silk fibroin on nanofibrils.
• Characterization of changes in contour statistics and bending response.
• Selective removal of the assembled layer to assess reversibility.

Main Results:

• Intrinsic kink defects in Hyphantria cunea silk nanofibrils significantly influence their bending response.
• Interfacial assembly of silk fibroin suppresses kink expression, smooths curvature, and shifts bending modes.
• The observed effects are largely reversible upon removal of the assembled layer.

Conclusions:

• Intrinsic defects play a crucial role in the mechanics of rigid biogenic nanofibrils.
• Interfacial assembly offers a method to tune single-fibril bending mechanics by reprogramming defect expression.
• This framework has implications for understanding interface-controlled mechanics in other biogenic fibrillar systems.