Noninvasive Diagnosis of Gastric Cancer Based on Breath Analysis with a Tubular Surface-Enhanced Raman Scattering Sensor

SERS-based breath analysis as an emerging technique has attracted increasing attention in cancer screening. Here, eight aldehydes and ketones in the human breath are reported as the VOC biomarkers identified by gas chromatography-mass spectrometry (GC-MS) and applied further for the noninvasive diagnosis of gastric cancer (GC) with a tubular SERS sensor. The tubular SERS sensor is prepared with a glass capillary loaded with ZIF-67-coated silver particles (Ag@ZIF-67), which offers Raman enhancement from the plasmonic nanoparticles and gas enrichment from the metal-organic framework (MOF) shells. The composite materials are modified with 4-aminothiophenol (4- ATP) to capture different aldehyde and ketone compounds. The tubular sensor is served simultaneously as a gas flow channel and a detection chamber, bringing a higher gas capture efficiency than the planar SERS sensor. As a proof-of-concept, the tubular SERS sensor is successfully employed to screen gastric cancer patients with an accuracy of 89.83%, based on the noninvasive, rapid, and easily operated breath analysis. The results demonstrate that the established breath analysis method provides an excellent alternative for the screening of GC and other diseases.