Ordered assemblies of peptide nanoparticles with only positive charge.

Area of Science:

• Colloid and Interface Science
• Materials Science
• Computational Chemistry

Background:

• Surface charge distribution on nanoparticles influences their self-assembly and solution behavior.
• Understanding these interactions is crucial for designing advanced materials and controlling colloidal systems.

Purpose of the Study:

• To computationally investigate the effect of surface charge distribution on nanoparticle self-assembly.
• To compare the solution behavior of single-charge (SC) nanoparticles with mixed-charge (MC) counterparts.

Main Methods:

• Computational design of coiled-coil 'bundlemer' nanoparticles with uniform (SC) and mixed (MC) surface charges.
• Simulation of nanoparticle behavior in solution under varying charge conditions.
• Machine learning optimization for inferring lattice structures.

Main Results:

• SC nanoparticles formed ordered nematic and columnar liquid crystal phases at low concentrations.
• MC nanoparticles with the same net charge and shape formed only amorphous, soluble aggregates.
• Mixtures of oppositely charged SC/MC particles formed porous lattices, while MC/MC mixtures formed amorphous aggregates.

Conclusions:

• Surface charge patchiness plays a critical role in determining nanoparticle self-assembly pathways.
• Uniform surface charges promote ordered structures, whereas mixed charges lead to amorphous aggregates.
• The findings underscore the importance of electrostatic interactions in controlling colloidal behavior and material formation.