Exhaled Breath Analysis for Assessment of IBD (Inflammatory Bowel Disease) Based on Electronic Nose System

Abstract

Introduction The diagnosis and differentiation of IBD (Inflammatory Bowel Disease) lacks a single gold standard. IBD commonly suffers from a delay in time from first occurrence of symptoms to diagnosis, especially in young patients with ileal disease, which hinders our ability to alter the progression of disease. Also, once the diagnosis of IBD is made its sub categorization into CD (Crohn’s Disease) or UC (ulcerative colitis) is critical for determining the optimal treatment strategy. It is important to identify at risk population that could benefit from a therapeutic approach [1]. Metabolomics studies have recently enter the field of IBD. A variety of studies have been conducted to be significantly different between CD, UC and heathy controls [2]. Limitation for use of metabolomics markers would be too time-consuming and expensive for assessment of IBD or invasive testing in cases. An ideal approach regarding IBD assessment is that breath metabolome offers great potential with simply, easy to use, non-invasive, cheap, rapid and reproducible [3]. An electronic nose system, which is an instrument comprises an array of chemical sensors with partial specificity and an appropriate pattern recognition system capable of recognition simple or complex odors [4], has been suggested a potential alternative as a novel approach for breath analytic technique.In this presentation, we introduce exhaled breath analysis for assessment of IBD from controls and CD from UC using an electronic nose system incorporating a solid-phase micro extraction (SPME) technique. Method We have been developed an electronic nose system composed one chip type array of chemical sensors, chamber, data acquisition system with microprocessor, and sampling system for SPME fiber operation for non-invasive heath care monitoring. The 2x4 sensor array in the system consisted of three oxides of SnO2, NiO2, and In2O3 using Au, Pt, and Pd as catalyst and fabricated on one chip by glancing angle deposition method [5]. A chamber was used to maintain the stable operating temperature of sensor array, and SPME fiber used transferring of exhaled breath samples for measurement. Figure 1 is shown electronic nose system which has been used for experimental work in the hospital. The collection of exhaled breath for IBD patients (23 CD, 32 UC) and 15 controls was carried out using tedlar bag in connection with mouthpiece having a saliva trap to prevent humidity. The SPME fiber coated 85μm Polyacrylate was inserted into the tedlar bag and exposed to the collected breath at an ambient temperature. The system exposed the fiber to the heated sensor array desorbing the volatile off the fiber directly onto the sensors in the chamber. The collection and measurement of expiration were conducted in a hospital after approval of the IRB (Institutional Review Board) at Dongsan Medical Center, Deagu, Korea. Results and Conclusions The primary result for collected data from electronic nose system is shown at Figure 2 using Linear Discriminant Analysis (LDA) algorithm. As shown in Figure 2, IBD patients and controls are distinguished, especially IBD subgroup between CD and UC is well separated each other. However, some samples from UC subgroup are mixed with controls. In this study, we implemented an electric nose system by fabricating a one chip sensors array incorporating SPME sampling technique. Throughout the experimental result, we investigate the possibility of classification between IBD including 2 subgroup discrimination and controls. However, we need more research to improve discrimination regarding UC and controls following by optimal VOCs markers between UC and control including instrument control.