Interface between Biomolecules and Electrical Nanostructures

Abstract

Recently, nanostructures have been extensively explored to investigate the interaction between biological molecules and nanomaterial. Since the dimension of the nanostructures is in accordance with the dimension of sub-cellular molecules, such as proteins, the nanostructures directly affect the functions and structures of the proteins and are easily combined with biological molecules. Among the nanostructures, nanowires (NWs) and nanotubes (NTs) have drawn much attention for the biological applications, because NWs and NTs can provide additional mechanical, optical, and electrical advantages for the nanostructure and biomolecule composites. However, it has not been extensively studied to visualize the interaction between nanostructures and biomolecules, optically and electrically. Here, we first demonstrated the sub-diffraction limit imaging of individual inorganic NWs under cells for the analysis of the interactions between the NWs and the focal adhesions of the cells. We successfully demonstrated the sub-diffraction limit optical imaging of sub-100 nm diameter NWs and developed an analysis method to extract the cross-sectional dimensions of the imaged NWs. Also, since this method is compatible with other fluorescence based methods and biological environments, we could image NWs as well as the focal adhesions of cells grown on the NWs to analyze the effect of NWs on the cell growth. Our works show that super resolution fluorescence imaging methods, which have been mostly utilized for biological imaging until now, can be a useful strategy for the imaging and the precise analysis of inorganic nanostructures with significant advantages over other imaging methods. Secondly, we demonstrated an olfactory-nanovesicle-fused carbon-nanotube-transistor biosensor (OCB) that mimics the responses of a canine nose for the monitoring of the response of olfactory receptors (cfOR5269) to hexanal, an indicator of the oxidation of food. OCBs allowed us to monitor the response of cfOR5269 to hexanal in real-time. Significantly, we demonstrated the detection of hexanal with an excellent selectivity capable of discriminating hexanal from analogous compounds such as pentanal, heptanal, and octanal. Furthermore, we successfully detected hexanal in spoiled milk without any pretreatment processes. Considering these results, our sensor platform should offer a new method for the assessment of food quality and contribute to the development of portable sensing devices. Finally, we demonstrated a peptide receptor-based bioelectronic nose (PRBN) that can determine the quality of seafood in real-time through measuring the amount of trimethylamine (TMA) generated from spoiled seafood. The PRBN allowed us to sensitively and selectively detect TMA in real-time at concentrations as low as 10 fM. Also, we were able to not only determine the quality of three kinds of seafood (oyster, shrimp, and lobster), but were also able to distinguish spoiled seafood from other types of spoiled foods without any pretreatment processes.