The human nose has the potential to detect up to a trillion different smells with its hundreds of scent receptors.
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However, even just catching a quick whiff of some chemicals called nerve agents could be lethal, even in small amounts. Currently, scientists reporting in ACS Sensors have come up with a selective and sensitive nerve gas sensor utilizing such human scent receptors. It reliably detected a replacement for deadly sarin gas in simulated tests.
Nerve gases are usually highly potent, needing highly sensitive sensors to detect them rapidly and precisely. One technique of boosting sensitivity integrates human scent receptors with nanomaterials like reduced graphene oxide to make a so-called “bioelectronic nose.”
However, since such nerve gases are still highly harmful even in laboratory settings, several researchers depend on safer, substitute molecules rather. When sarin or soman nerve agents are considered, dimethyl methylphosphonate (DMMP) is known as a common replacement. Earlier, the receptor protein hOR2T7 has been utilized to detect DMMP, but it can only do so when the nerve agent substitute was in the form of a liquid, instead of gas.
Hence, Tai Hyun Park, Jyongsik Jang, and collaborators wished to design a “nose” that was both highly selective and sensitive for the gaseous form, utilizing nanodiscs consisting of the hOR2T7 receptor.
For nanodiscs to be created, scientists integrated hOR2T7 with a membrane scaffold protein and other lipids. The hOR2T7 squeezed within the scaffold, similar to an inflatable innertube, was kept upright to readily bind DMMP.
Further, the discs were stuck to the decreased graphene oxide layer of the sensor, which was decorated with nickel atoms to assist in holding the discs in the correct position.
Even while being exposed to compounds with similar shapes or smells, the sensor just detected DMMP and was highly sensitive to sense a concentration as low as 0.037 parts per billion.
Also, the team displayed that the device was ideal for real-world scenarios, like smoky conditions and also during repeat tests. Although additional experiments are required, the scientists say that this work displays that human scent receptors are beneficial components for highly selective and sensitive gas sensors.
Journal Reference:
Kim, S-O., et al. (2023) Ni-rGO Sensor Combined with Human Olfactory Receptor-Embedded Nanodiscs for Detecting Gas-Phase DMMP as a Simulant of Nerve Agents. ACS Sensor. doi.org/10.1021/acssensors.3c00744
Source: https://www.acs.org/