Artificial Sensory System with High Reliability for Investigation on Food Spoilage

Abstract

An artificial sensor based on nanomaterials has been great interest in research on artificial sensory systems because of their excellent sensitivity and selectivity. The fundamental studies of mammalian sensory systems and the hybridization of bio- and nanomaterials are necessary for the development of the remarkable performance of sensors. In this dissertation, we have investigated on the activity of various sensory receptor proteins and related responses. Furthermore, we developed artificial sensory systems for the assessment of food quality with high reliability which could mimic the response of mammalian sensory system. First, we have developed a multiplexed bioelectronics sensor (MBS) that could distinguish various odorants and tastants indicating the food contaminations. We demonstrated that the MBS could monitor the responses of various sensory receptors, showing different binding characteristics. The MBS exhibited a human-like performance in a mixture solution of various target molecules of receptors with 1 pM detection limit. In addition, our sensor platform could recognize food contamination indicators from the real food samples via the combinations of responses of different receptors. Moreover, we developed a highly-stable and oriented nanodiscs (NDs)-based bioelectronic nose (ONBN) for the detection of CV. TAAR13c-embedded nanodiscs (T13NDs) were constructed with TAAR13c produced in E. coli. High-quality T13NDs efficiently mimic native binding pockets and lead highly sensitive and selective detections of CV. Here, the immobilization of T13NDs with a desired orientation on floating electrodes via linker molecules enabled the active binding site to recognize target molecules, which results in high sensitivity and selectivity of our sensor platform. In addition, an ONBN quantitatively detect CV in real food samples by spoilage periods. These results indicate that our ONBN platform based on GPCR-conjugated FET is a new method for the detection of death-associated odor and has a potential on practical bioelectronic sensor applications. Additionally, in the last part of this dissertation, we discussed about the control of enzymatic reaction via nanostructured conducting polymer. We reported a novel bio-chip strategy for control of enzymatic reaction in real-time via electrical stimuli. This technique is named as a bio-switch chip (BSC). We fabricated BSC structures using polypyrrole (Ppy) with entrapped glucose oxidase (GOx) and showed the switching performance of enzymatic reaction in real-time. The introduction of a negative bias voltage on the BSC structure resulted in the 20-folds increased glucose oxidation reaction than that without a bias voltage. Furthermore, we could control the enzymatic reaction on specific regions because the BSC structures could be fabricated on specific regions. In consideration of the fact that enzymes enable useful and versatile to bio-chemical reactions, the capability to control the enzymatic reactions using simple electrical signals could open up various applications in the field of biochips and biochemical industries.