Chitosan as stabilizing agent for negatively charged nanoparticles.

Area of Science:

• Materials Science
• Nanotechnology
• Biochemistry

Background:

• Chitosan, a positively charged biopolymer, can stabilize negatively charged nanoparticles.
• Silk fibroin nanoparticles (SFN) and citrate gold nanoparticles (AuNP) aggregate at physiological ionic strength due to their negative Z-potential.

Purpose of the Study:

• To investigate the stabilizing behavior of chitosan for AuNP and SFN under increasing ionic strength.
• To determine how chitosan concentration and component ratios influence nanocomposite stability and size.
• To elucidate the interaction mechanisms between chitosan and silk fibroin monomers using molecular modeling.

Main Methods:

• Experimental measurements of nanoparticle behavior in solution.
• Varying ionic strength, chitosan concentration, and component ratios.
• Molecular modeling to study chitosan-silk fibroin interactions and energetic contributions.

Main Results:

• Optimal conditions were identified for producing the smallest and most homogeneous stable nanocomposites.
• Chitosan demonstrated significant stabilization of both AuNP and SFN against aggregation.
• Molecular modeling provided insights into the specific interactions driving stabilization.

Conclusions:

• Chitosan effectively prevents aggregation of AuNP and SFN in solutions with elevated ionic strength.
• Two distinct organizational mechanisms for chitosan's stabilizing effect were proposed.
• The findings offer a pathway for designing stable nanocomposite materials.