Nondestructive methodology with discerning fruit freshness biomarker compounds using olfactory receptor nanodisc-loaded graphene transistors

Noninvasive and facile methodologies for the assessment of fruit freshness are essential for the determination of fruit ripeness. Fruits emit characteristic aroma molecules during maturation, and the selective and sensitive detection of these scents is highly challenging. Herein, a novel nondestructive methodology for discerning fruit freshness biomarker compounds based on a target-specific olfactory receptor-loaded transistor for detecting aroma molecules at ppb levels is proposed. This fruit freshness discrimination platform can detect the representative aromas caused by compounds including iso-amyl acetate, amyl-butyrate, geraniol, and β-citronellol that are emitted by each fruit species, such as bananas, grapes, and apricots, and has a lower limit of detection below femtomolar concentrations. Measurement of the selective binding affinity between the olfactory receptor and aroma molecules was conducted using biosimulation, and the experimental results were compared with the sensor response. The fabricated sensor exhibited superior performance in determining the ripeness of fruits with discerning fruit freshness biomarker compounds and presented promising potential for application in agriculture and other industry fields as an assessment platform for detecting various aromatic molecules. Our findings highlight the broad utilization of newly developed sensor platforms as standards for distinguishing freshness.