Ultrathin water layers on mannosylated gold nanoparticles

Area of Science:

• Nanotechnology
• Surface Chemistry
• Biophysics

Background:

• Gold nanoparticles are versatile platforms for sensing and drug delivery.
• Mimicking viral surface proteins is crucial for understanding virus-host interactions.
• The effect of humidity on nanoparticle surface interactions is not fully understood.

Purpose of the Study:

• To investigate the impact of air humidity on the hydration and structural properties of two distinct gold nanoparticle systems.
• To compare the water adsorption behavior of nanoparticles functionalized with oligo(ethylene glycol) versus a dimannoside ligand.
• To explore the potential applications of these glyconanoparticles in biosensing and viral transmission modeling.

Main Methods:

• Characterization using electron microscopy, dynamic light scattering, and infrared spectroscopy.
• Atomic force microscopy (AFM) and vibrational sum frequency generation (VSFG) spectroscopy under variable humidity.
• Testing on hydrophilic and hydrophobic surfaces and with different AFM tips.

Main Results:

• Dimannoside nanoparticles exhibited preferential hydration and conformational changes in ligands upon humidity increase.
• AFM revealed sub-nanometer topographic changes in nanoparticles due to water adsorption.
• Dimannoside nanoparticles condensed ultrathin water layers with increasing humidity, while oligo(ethylene glycol) nanoparticles showed minimal humidity-dependent water adsorption.

Conclusions:

• Glycosylated nanoparticles display unique hydration properties influenced by ligand structure.
• Understanding these hydration dynamics is vital for developing advanced biosensors.
• The findings contribute to modeling the transmission mechanisms of airborne viruses like influenza.