Piezoresistive membrane surface stress sensors for characterization of breath samples of head and neck cancer patients

Abstract

For many diseases, where a particular organ is affected, chemical by-products can be found in the patient's exhaled breath. Breath analysis is often done using gas chromatography and mass spectrometry, but interpretation of results is difficult and time-consuming. We performed characterization of patients' exhaled breath samples by an electronic nose technique based on an array of nanomechanical membrane sensors. Each membrane is coated with a different thin polymer layer. By pumping the exhaled breath into a measurement chamber, volatile organic compounds present in patients' breath diffuse into the polymer layers and deform the membranes by changes in surface stress. The bending of the membranes is measured piezoresistively and the signals are converted into voltages. The sensor deflection pattern allows one to characterize the condition of the patient. In a clinical pilot study, we investigated breath samples from head and neck cancer patients and healthy control persons. Evaluation using principal component analysis (PCA) allowed a clear distinction between the two groups. As head and neck cancer can be completely removed by surgery, the breath of cured patients was investigated after surgery again and the results were similar to those of the healthy control group, indicating that surgery was successful.

Recent Advances in Nanomechanical Membrane-Type Surface Stress Sensors towards Artificial Olfaction

“…Cancer is one of the most sever diseases in the world with the highest mortality. As a preliminary study, Loizeau et al demonstrated the cancer diagnosis through breath analysis using an MSS array [ 154 , 155 ]. They used 16 different polymers as a receptor material, which have different chemical and physical properties to express a wide range of chemical selectivity.…”