Kao unveils ScentVista 400 to decode human sense of smell

Kao Corporation has unveiled ScentVista 400, a technology that analyzes olfactory receptor responses to smell.

Kao says its Sensory Science Research Laboratory is the “first in the world to successfully express on the surface of cultured cells almost all of the approximately 400 types of human olfactory receptors.”  

The chemical company states that the human nose contains approximately 400 olfactory receptors. Each of these receptors acts as a sensor to detect specific smells and distinguish them from the hundreds of thousands of odors that exist. The receptors transmit this information to the brain, allowing humans to detect smells.

“In order to investigate how humans sense odors, it is necessary to ascertain how olfactory receptors respond when they recognize odorants. Because direct experimentation within the human nose is not feasible, researchers commonly use cultured cells instead to express olfactory receptors,” explains Kao.

In the human nose, the receptors are present on the cell surface. But on cultured cells, they often fail to localize on the cell surface and thus remain in the cell. This blocks them from detecting odorants, resulting in only about 10% of human olfactory receptors having been successfully studied until now.

Kao used its technology, developed in 2023, to establish a new method for conducting a comprehensive analysis of 400 types of olfactory receptor responses, including those previously uncharacterized.

“Using these response patterns, Kao sought to elucidate the mechanisms underlying odor recognition and advance understanding of the human sense of smell,” says the company.

The ScentVista 400 detects if an odorant is pleasant or unpleasant by emitting a light.Olfactory challenges

Kao’s research team investigated human olfactory receptors that had previously been difficult to analyze.

The researchers identified specific amino acids that may prevent the receptors from appearing on the surface of the cultured cells. The amino acids were then exchanged with alternatives that allow almost all receptors to be successfully expressed on the surface of the cultured cells — thereby enabling odor recognition.

The ScentVista 400 detects if an odorant is pleasant or unpleasant by emitting a light, and the intensity of the light confirms the receptor’s response.

When investigating the human olfactory receptor respondents, the results showed that similar odors have similar receptor response patterns.

Kao exemplifies rose oil, which is made from petals, and geranium oil, which is extracted from leaves and stems. 

The two ingredients have similar scents despite being derived from different kinds of flowers and various parts of the plant. The findings showed that the olfactory receptor response patterns of rose oil and geranium oil are also similar.

Meanwhile, similar smells may also differ in olfactory receptor response patterns when given in different concentrations. Kao investigated indole, a substance that has a pleasant, jasmine-like floral scent at low concentrations, but at high concentrations, it had an unpleasant fecal odor.

Kao says these findings demonstrate that the human sense of smell is based on patterns of olfactory receptor activation.