Advances in Mid-Infrared Spectroscopy-Based Sensing Techniques for Exhaled Breath Diagnostics.

Ramya Selvaraj,Nilesh J Vasa,Boris Mizaikoff,S M Shiva Nagendra

doi:10.3390/molecules25092227

Ramya Selvaraj, Nilesh J Vasa + Show 2 more

Open Access

https://doi.org/10.3390/molecules25092227

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Abstract

Human exhaled breath consists of more than 3000 volatile organic compounds, many of which are relevant biomarkers for various diseases. Although gas chromatography has been the gold standard for volatile organic compound (VOC) detection in exhaled breath, recent developments in mid-infrared (MIR) laser spectroscopy have led to the promise of compact point-of-care (POC) optical instruments enabling even single breath diagnostics. In this review, we discuss the evolution of MIR sensing technologies with a special focus on photoacoustic spectroscopy, and its application in exhaled breath biomarker detection. While mid-infrared point-of-care instrumentation promises high sensitivity and inherent molecular selectivity, the lack of standardization of the various techniques has to be overcome for translating these techniques into more widespread real-time clinical use.

Highlights

Human breath has always been a matrix of interest for disease diagnostics and monitoring owing to its inherently noninvasive access
Variations to the conventional laser spectroscopic method to improve the sensitivity of the sensor system include multi-pass spectroscopy (MUPASS) and cavity ring-down spectroscopy (CRDS), which are most widely used for such applications
Many studies have shown that ammonia in exhaled breath can be used for detecting chronic kidney disease (CKD), (CKD),because, because,ininpatients patientswith withCKD, CKD, the accumulated urea cannot be excreted by kidney disease the accumulated urea cannot be excreted by the kidney disease (CKD), because, in patients with

Summary

Introduction

Human breath has always been a matrix of interest for disease diagnostics and monitoring owing to its inherently noninvasive access. Breath analysis can reduce dependence on invasive diagnostics, The list of VOCs and inorganic compounds and their relation to potential disease states, as such as bronchial biopsies and bronchoalveolar lavage for preliminary assessments Variations to the conventional laser spectroscopic method to improve the sensitivity of the sensor system include multi-pass spectroscopy (MUPASS) and CRDS, which are most widely used for such applications Reflection losses, andhas theto channel length be for individual breath the detection this technique for breathlimits gas analysis be further combined gases under limits study.ofHowever, the detection of this can technique for improved breath gaswhen analysis can be with other analytical methods. 0.15 ppb CEAS: cavity-enhanced absorption spectroscopy, ICOS: integrated cavity output spectroscopy, CALOS: cavity leak-out absorption spectroscopy, TDLAS: tunable diode laser absorption spectroscopy, MP: multipass, WMS: wavelength modulation spectroscopy, DAS: direct absorption spectroscopy, CRDS: cavity ring-down spectroscopy, QCL: quantum cascade laser, ECDL: external cavity diode laser, DFB-ICL: distributed feedback-intracavity laser, HCF: hollow core fibre, PPLN: periodically poled lithium niobate

Photoacoustic Spectroscopy for Breath Gas Analysis

Ammonia

Challenges and Perspectives