High-performance olfactory receptor-derived peptide sensor for trimethylamine detection on the pyramid substrate structure

In our daily life, people are commonly exposed to trimethylamine (TMA) and suffered from a variety of diseases. Therefore, we are desperately in need of the real-time monitoring of TMA with convenience and high sensitivity. In this study, a pyramid substrate structure was developed to manufacture a high-performance TMA sensor, where olfactory receptor-derived peptides (ORPs) as the sensing material were chemically connected to singlewalled carbon nanotubes (SWCNTs). First, the pyramid structure on silicon substrates was fabricated by chemical etching method. Then, SWCNTs were attached to the pyramid structure substrate. After that, the surface of SWCNTs were modified with thioester in the ester exchange reaction and connected to the ORPs whose N-terminus bore a cysteine residue to the thioester by natural chemical ligation. Using this approach, the ORPs-CNTs sensor on pyramid Si substrate was capable of detecting gaseous TMA with a concentration as low as 0.01 ppt and the responsivity was improved significantly compare with the sensor on flat Si substrate as well. The sensor was also shown excellent sensitive and stable for TMA detection by selectivity and repeatability measurements. The results proved the availability and the potential usage of the pyramid structure for sensors fabrication and the potential of these TMA sensors applied in food safety, diseases monitoring and environmental protection.