Volatolomics analysis of lung and colon cancer using terahertz and infrared spectroscopy

Abstract

Terahertz and infrared spectroscopy are effective analytical spectroscopic techniques to identify and study the conformation and molecular interaction of the biomolecules. It has a huge potential in cancer diagnosis because these spectroscopies are non-invasive technique and do not require labelling for tissues and cells. Volatolomics analysis is a technique to analyse the volatile organic compounds (VOCs) emitted and released by human metabolites, which are not limited to breathe analysis. VOCs that are released by cancerous cells can be one of the bio-diagnostics techniques to diagnose cancer. Although studies on breath analysis have been widely carried out, the study of the volatolomics analysis by using Fourier transform infrared spectroscopy (FTIR) and Terahertz time-domain spectroscopy (THz-TDS) is still new. Both FTIR and THz-TDS instruments are installed with a gas cell sampling tools by absorption technique to analyse and detect the key species released from the VOCs. Lung cancer (NCL-H1299) and colon cancer (COLO320DM) cell lines are uas samples to identify the key species of each of the cancerous cells. The experiment has been verified and validated by comparing with control samples such as normal lung (MRC-5) cell lines, normal colon (CCD112CoN) cell lines, empty flask, air from the culture media and normal lab air. All the samples have been cultured into different sealed flasks for 24 to 120 hours, before the VOCs are collected and transferred into the gas cells to analyse using FTIR and THz-TDS. Hydrogen chloride and benzamide have been identified as key species for lung and colon cancer, respectively. These findings have been verified and validated by using residual gas analyser (RGA), gas chromatography – mass selective detector (GC-MSD), and confirmed by earlier literatures. A chemometric statistical analysis also has been applied to this study to extract the important information of the biochemical data from the VOCs with the greatest discriminative power and highest precision. These findings demonstrate the potential use of FTIR and THz-TDS as clinical tools through the volatolomics analysis. In addition, more work is needed if it is to be applied in clinical practice.