Various threats such as explosives, drugs, environmental hormones, and spoiled food manifest themselves with the presence of volatile organic compounds (VOCs) in our environment. In order to recognize and respond to these threats early, the demand for highly sensitive and selective electronic noses is increasing. The M13 bacteriophage-based optoelectronic nose is an excellent candidate to meet all these requirements. However, the phage-based electronic nose is still in its infancy, and strategies that include a systematic approach and development are still essential. Here, we have integrated theoretical and experimental approaches to analyze the correlation between the surface chemistry of genetically engineered phage and the phage-based optoelectronic nose properties. The reactivity of the genetically engineered phage color film to some VOCs were quantitatively analyzed, and the correlation with the binding affinity value calculated by Density-functional theory (DFT) was compared. This demonstrates that phage color films have controllable reactivity through a genetic engineering. We have selected phages that are advantageous in distinguishing each VOCs in this work through hierarchical cluster analysis (HCA). The reason for this difference was verified through the optimized geometry calculated by DFT. Through this, it was confirmed that the tryptophan-based and the Histidine-based of genetically engineered phage film are important in distinguishing the VOCs (Y-hexanolactone, 2-isopropyl-4-methylthiazole, ethanol, acetone, ethyl acetate, and acetaldehyde) used in this work to evaluate the peach freshness quality. This was applied to the design of a field-applied phage-based optoelectronic nose and verified by measuring the freshness of the actual fruit.
Keywords: Bacteriophage; Bioelectronic nose; Biomaterials; Genetic engineering; Surface chemistry.
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