Mosquitoes are one of the most dangerous creatures on the planet, responsible for transmitting deadly diseases such as malaria, dengue fever, and Zika virus. With the rise of insecticide-resistant mosquitoes, finding effective ways to prevent bites has become more critical than ever. Researchers have long been studying natural and synthetic materials that could act as a barrier against mosquito bites. In recent years, cellulose nanocrystals have emerged as a promising option due to their unique properties. In this article, we will explore the potential of cellulose nanocrystals as a barrier against mosquito bites and how this material could change the way we protect ourselves from these disease-carrying pests.
A study published in the Proceedings of the National Academy of Sciences (PNAS) Nexus Journal highlights the use of cellulose nanocrystals (CNCs) as a barrier against mosquito bites. Mosquitoes can carry a number of parasitic illnesses, including yellow fever, malaria, zika, and chikungunya, presenting significant public health risks. Eradicating mosquito populations is one approach being studied to tackle these health concerns. Other strategies include vaccines and treatments or prevention methods, such as topical repellents. These contain either natural odorant compounds, such as citronella, or synthetic non-odorant compounds, like N, N-diethyl-meta-toluamide, each acting as active molecules on olfactory receptors, rendering the skin unappealing to mosquitoes. Despite their effectiveness, they have limited ranges of protection.
CNCs result from the acid hydrolysis of amorphous cellulose and are readily water-soluble. At low concentrations, they appear transparent in water and can be produced into thin films through casting and drying. CNCs also show liquid crystal behavior at lower concentrations, making them useful for stable dispersion. These characteristics led researchers to explore the potential for CNCs to reduce the rate of mosquito bites in a scientific study.
The study involved testing CNCs on Aedes aegypti mosquitoes to examine their barrier to bites. The researchers began the test by exposing one researcher’s bare skin to 15 female mosquitoes for ten minutes, leaving a defined area of skin exposed regardless of whether topical CNC was applied or not. To ensure the CNC did not crack on the skin, suggesting destruction of the barrier effect, glycerol was incorporated into the aqueous solution. The CNC-glycerol application notably reduced the number of blood-fed mosquitoes. Further analysis found that fewer mosquitoes had landed on the hand covered with CNCs, indicating that the barrier effect was physical or chemical.
Another experiment examined the chemical properties of the CNC-glycerol mixture, using an artificial feeding system called Hemotek to remove human bias. The researchers observed membrane filters collecting eggs, analyzed by camera equipment under the same conditions for both CNCs and control groups (parafilm). The team found a considerable difference in egg reduction, with results indicating that CNCs acted as a barrier for the mosquitoes. Moreover, indole was added to the CNC-glycerol solution since previous reports suggested its role in inhibiting host attraction in such mosquitoes. The CNC-indole coating proved most effective in reducing egg deposition on the membrane filter. The final headspace experiment on whether CNC films could prevent ammonium hydroxide from permeating confirmed that CNC acted as a chemical barrier.
The results suggest that CNCs can reduce the rate of blood feeding by A. aegypti mosquitoes when applied to the hand or the artificial Hemotek membrane feeding system. These tests confirm that CNCs can be used as chemical camouflage, significantly reducing the laying of eggs. When insecticidal was added to CNC-glycerol, the CNC barrier effect was increased. Given the biocompatibility and self-assembly characteristics of CNCs, this research highlights their potential use as next-generation personal protective equipment.
In conclusion, cellulose nanocrystals offer a promising solution to the age-old problem of mosquito bites. With their incredible barrier properties and low toxicity, they present a safer and more effective alternative to traditional mosquito repellents. While still in development, cellulose nanocrystals could soon become a go-to solution for protecting against mosquito-borne illnesses. As we continue to explore the potential of this remarkable material, the future looks brighter in our fight against mosquitoes, and the diseases they carry.
