Mosquito bite prevention through self-assembled cellulose nanocrystals.

Area of Science:

• Materials Science
• Entomology
• Nanotechnology
• Biomaterials

Background:

• Mosquitoes pose a significant global health threat, causing millions of infections and thousands of deaths annually.
• Current mosquito repellents, like DEET and essential oils, often rely on volatile compounds, require organic solvents, and have limitations.
• There is a need for novel, effective, and potentially safer mosquito protection methods.

Purpose of the Study:

• To investigate the potential of cellulose nanocrystals (CNCs) as a barrier material for mosquito protection.
• To evaluate the efficacy of CNC coatings in preventing mosquito feeding and deterring egg-laying.
• To assess the chemical barrier properties of CNC films against mosquito attractants.

Main Methods:

• Application of a thin cellulose nanocrystal (CNC) coat to human skin.
• Artificial feeding assays using *Aedes aegypti* mosquitoes.
• Assessment of egg-laying reduction post-exposure to mammalian blood.
• Headspace experiments to evaluate the barrier properties against ammonium hydroxide vapor.

Main Results:

• A significant 80% decrease in mosquito feeding was observed on human skin treated with a CNC coat.
• CNC acted as a chemical camouflage, reducing feeding in artificial assays with *Aedes aegypti*.
• Combining CNC with indole resulted in a 99.4% reduction in egg-laying after exposure to blood.
• CNC films effectively blocked the passage of ammonium hydroxide vapor, demonstrating chemical barrier properties.

Conclusions:

• Cellulose nanocrystals (CNCs) show promise as a novel, bio-based material for mosquito control.
• CNC coatings can act as both a physical and chemical barrier, reducing mosquito feeding and reproduction.
• The findings suggest CNCs could be a sustainable alternative to conventional insect repellents.