Major Urinary Proteins on Nanodiamond-Based Resonators Toward Artificial Olfaction

A new bio-sensing platform based on major urinaryproteins (MUPs) from the mouse as chemical recognitionelements has been developed. The transducers were surfaceacoustic devices coated with diamond nanoparticles as an intermediatelayer enabling covalent attachment of the proteins.The resulting sensors detected 2,4-Dinitrotoluene, 4-Nitrotoluene,and 2-Isobutyl-3-methoxypyrazine at ppb levels. The best sensorshowed a sensitivity of 24 000 Hz · ppm−1 to 2, 4-DNT whengrafted with the protein MUP20. Trends in the sensitivity ofthe various VOC sensors were compared with the associationconstant values Ka of the proteins to target ligands measured bycompetitive assay in liquid phase. The system is able to detectanalytes both in liquid as well as vapor phase and indicate thatMUPs are robust bio-recognition elements that can be utilized inartificial olfaction applications.