Detection of colorectal cancer biomarkers in the presence of interfering gases

• We have realized and characterized metal oxide sensors.
• We have applied sensor technology to colorectal cancer (CRC) biomarkers detection.
• We have tested sensors response to single VOCs, both in wet and in dry conditions.
• We have made interference tests among tumor markers and other interferers.
• We have identified sensors which best discriminate CRC biomarkers from interferers.

Medical studies have shown that tumor growth is accompanied by protein changes that may lead to the peroxidation of the cell membrane, with consequent emission of volatile organic compounds (VOCs). VOCs can be detected through breath or intestinal gases and are biomarkers for colorectal cancer (CRC). The analysis of VOCs represents a non-invasive and potentially inexpensive pre-screening technique. An array of chemoresistive gas sensors, based on screen-printed Metal OXide (MOX) semiconducting films, has been selected to identify gaseous compounds of oncological interest, i.e. benzene, 1-iodo-nonane and decanal, from the main interferers that can be found in the intestine. MOX sensors are able to detect concentrations down to about 10th ppb, as experimentally proven in previous works, so they can identify very slight differences in concentration among gas mixtures. In this work it has been proven that the array used is able to identify tumor markers singularly and in combination with other gases both in wet and dry conditions. Moreover, the sensors chosen can discriminate target VOCs from interferers even at low concentrations.