Distinction of primary alcohols based on dynamic responses of a phospholipid molecular layer obtained using artificial sniffing

We investigated a novel odor sensing system based on artificial sniffing, i.e., detecting dynamic responses in a phospholipid molecular layer under periodic perturbation, to identify primary alcohols. Conventional gas sensors identify reduced substances based on one-dimensional information at a steady state, which limits their ability to distinguish compounds with similar chemical structures using a single sensor. In contrast, the proposed system leverages the dynamic responses of a 1,2-dipalmitoyl- sn -glycero-3-phosphocholine (DPPC) molecular layer on water under periodic exposure of volatile substances to obtain multi-dimensional information. We observed that the dynamic surface-tension responses systematically varied with the carbon number of primary alcohols. These responses could be reproduced by numerical calculations based on the dynamics of primary alcohols on the phospholipid molecular layer under periodic perturbation of the volatile flow. To physicochemically evaluate the interaction between DPPC and alcohol as a function of the carbon number, we performed attenuated total reflection Fourier-transform infrared spectrometry, differential scanning calorimetry, small-angle X-ray scattering, and wide-angle X-ray scattering analyses. Our findings can contribute to the development of dynamic sensors based on spatio-temporal information, such as dynamic responses and the arrangement of the DPPC molecular layer in the presence of volatile substances.