With the loss of taste and smell a key symptom of COVID-19, researchers have made a nanoparticle breakthrough which could open the way to the ability to restore or enhance the sense.
The news has a range of medical implications including the ability to reverse the loss of smell and taste but could have applications for the treatment of a range of conditions.
An Auburn University research team has made the first discovery of metal nanoparticles occurring naturally in an animal body, specifically zinc nanoparticles in nose cells, which has implications in possibly restoring or enhancing an animal’s or person’s sense of smell.
“Scientists have long known animal tissue has minerals in ionic and atom-bound states, but no one knew metal nanoparticles were naturally in the animal body,” said Vitaly Vodyanoy, professor of physiology in the College of Veterinary Medicine. “This is the first time a third state of metal has been observed in the body.”
The study, “Endogenous zinc nanoparticles in the rat olfactory epithelium are functionally significant,” was published in the journal, Nature Scientific Reports.
The importance of the finding is that metal nanoparticles donate or accept many more electrons toward enzymatic reactions than available from single, metal ions. Nanoparticles are structures composed of many atoms, while ions are electrically charged atoms created by the loss or gain of one or a few electrons.
“Some scientists suggest electrons trigger the sense of smell,” Prof. Vodyanoy said. “Therefore, metal nanoparticles, which can operate with many electrons, have an advantage over metal ions in smell enzymatic reactions.”
“This is also the first study to show zinc is in the cilia,” he said. “It’s not a single atom, but nanoparticles with 50 to a few hundred atoms of metal. We proved zinc naturally exists in the animal body, which we believe would include humans.”
The finding of zinc nanoparticles builds upon Prof. Vodyanoy’s prior research, dating to 2005, and should open the door for future research globally into restoring or enhancing the sense of smell, as well other areas involving enzymatic reactions.
“Our current study found that natural zinc from the olfactory neurons’ cilia produces the same increase as nanoparticle-engineered zinc,” he said. “We previously found if you add zinc, either natural or engineered, with a puff of air to anything with an odour, we see a three-times increase in an animal’s olfactory response,” He explained.
Prof. Vodyanoy says the discovery of zinc nanoparticles will add to the knowledge base of how zinc and olfactory receptors work and should advance the understanding of the sense of smell. Restoring or enhancing the sense of smell is one possible future benefit.
“Diseases like Parkinson’s, Alzheimer’s and now COVID-19 often cause a person to lose the sense of smell,” he said. “I believe we could research ways to add a small and safe amount of zinc to food or drink, possibly as an aerosol, to allow patients to smell these foods again.
“Aromas are important in perception of our food and beverages. Food industries use a variety of chemicals, essential oils and botanicals to accentuate the smell of food. Zinc nanoparticles can be used for the enhancement of aromas in food and to make it more attractive and healthier.”
He also says zinc has been shown to play a role in the memory process, and his study could provide valuable information to those studying Alzheimer’s.