Interactions at the silica-peptide interface: the influence of particle size and surface functionality

Area of Science:

• Surface Chemistry and Nanomaterials Science
• Biomolecular Interactions and Nanotechnology

Background:

• Silica nanoparticles (SiNPs) are versatile due to their interfacial properties.
• Understanding interfacial interactions is key for SiNP applications but remains incomplete.
• Biomolecular adsorption on SiNPs is influenced by particle characteristics.

Purpose of the Study:

• To investigate how SiNP particle size and surface functionalization affect small biomolecular binder adsorption.
• To elucidate the influence of peptide properties on binding to SiNPs.
• To understand the mechanisms governing adsorption at the silica/aqueous interface.

Main Methods:

• Utilized fully characterized SiNPs (28-500 nm) and functionalized SiNPs (cationic, hydrophobic).
• Employed small silica-binding peptides with varying physicochemical properties.
• Investigated adsorption and binding affinity using a fluorimetric assay at pH 7.4.
• Characterized surface chemistry using X-ray photoelectron spectroscopy (XPS).

Main Results:

• Minimal surface functionalization (below monolayer coverage) caused significant changes in peptide adsorption.
• Peptide adsorption increased with increasing SiNP size, independent of peptide properties.
• Larger SiNPs showed a shift towards dominant electrostatic binding mechanisms.

Conclusions:

• SiNP particle size and surface functionality are critical parameters influencing biomolecule uptake.
• These factors modulate or select specific binding modes at the silica/peptide interface.
• Findings are applicable to designing interfaces for biomedical applications like drug delivery and understanding biopanning selection.