iHWG-MOX: A Hybrid Breath Analysis System via the Combination of Substrate-Integrated Hollow Waveguide Infrared Spectroscopy with Metal Oxide Gas Sensors

Glöckler, Johannes; Jaeschke, Carsten; Kocaöz, Yusuf; Kokoric, Vjekoslav; Tütüncü, Erhan; Mitrovics, Jan; Mizaikoff, Boris

doi:10.1021/acssensors.9b02554

Cited by 20 publications

(6 citation statements)

References 44 publications

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“…More recently, another hybrid analytical device was developed combining eNose technology based on semiconducting metal oxide (MOX) sensors with FTIR-iHWG gas sensors to enhance the data space enabling the analysis of complex sample mixtures (e.g., exhaled breath). 61 A 75 mm straight iHWG was coupled to a compact FTIR spectrometer, and samples were first injected into the FTIR-iHWG system followed by a flow-through analysis within an MOX gas sensor array. The device was evaluated for the simultaneous detection of methane and carbon dioxide at low parts per million concentrations.…”

Section: Other Applicationsmentioning

confidence: 99%

From Light Pipes to Substrate-Integrated Hollow Waveguides for Gas Sensing: A Review

Barreto

Kokoric²,

Petruci

et al. 2021

ACS Meas. Sci. Au

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Absorption-based spectroscopy in the mid-infrared (MIR) spectral range (i.e., 2.5–25 μm) is an excellent choice for directly sensing trace gas analytes providing discriminatory molecular information due to inherently specific fundamental vibrational, rovibrational, and rotational transitions. Complimentarily, the miniaturization of optical components has aided the utility of optical sensing techniques in a wide variety of application scenarios that demand compact, portable, easy-to-use, and robust analytical platforms yet providing suitable accuracy, sensitivity, and selectivity. While MIR sensing technologies have clearly benefitted from the development of advanced on-chip light sources such as quantum cascade and interband cascade lasers and equally small MIR detectors, less attention has been paid to the development of modular/tailored waveguide technologies reproducibly and reliably interfacing photons with sample molecules in a compact format. In this context, the first generation of a new type of hollow waveguides gas cellsthe so-called substrate-integrated hollow waveguides (iHWG)with unprecedented compact dimensions published by the research team of Mizaikoff and collaborators has led to a paradigm change in optical transducer technology for gas sensors. Features of iHWGs included an adaptable (i.e., designable) well-defined optical path length via the integration of meandered hollow waveguide structures at virtually any desired dimension and geometry into an otherwise planar substrate, a high degree of robustness, compactness, and cost-effectiveness in fabrication. Moreover, only a few hundred microliters of gas samples are required for analysis, resulting in short sample transient times facilitating a real-time monitoring of gaseous species in virtually any concentration range. In this review, we give an overview of recent advancements and achievements since their introduction eight years ago, focusing on the development of iHWG-based mid-infrared sensor technologies. Highlighted applications ranging from clinical diagnostics to environmental and industrial monitoring scenarios will be contrasted by future trends, challenges, and opportunities for the development of next-generation portable optical gas-sensing platforms that take advantage of a modular and tailorable device design.

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Section: Other Applicationsmentioning

confidence: 99%

From Light Pipes to Substrate-Integrated Hollow Waveguides for Gas Sensing: A Review

Barreto

Kokoric²,

Petruci

et al. 2021

ACS Meas. Sci. Au

Self Cite

View full text Add to dashboard Cite

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“…Alternatively, mid-infrared (MIR) spectroscopic technology provides a fundamental advantage for the chemical identification of target analytes via the detection of characteristic vibrational frequencies. [6,10,11] For portable MIR devices, miniaturization of the components and sensing with attenuated total reflection (ATR) using on-chip waveguides (WGs) increases device sensitivity due to the generation of continuous evanescent waves along the WG surface, in comparison to the discrete reflections in traditional bulky instrumentation. [11,12] Nevertheless, gas detection in the vicinity of the WGs of the miniaturized devices still has its challenges due to the need for long optical path lengths, [13,14] limited penetration depth of the evanescent field, [15] low concentration of the gaseous analytes in the gas phase, and their weak adsorption onto the pristine sensor surfaces.…”

Section: Introductionmentioning

confidence: 99%

Silane‐Modified Mesoporous Silica Nanocoatings for Selective Mid‐Infrared Waveguide‐Based Gas Sensing

Husseini

Zhou

et al. 2022

Adv Materials Inter

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This paper reports the use of silane monolayers of different polarities to enable recognition and selective interfacial enrichment of nonpolar versus polar gases for spectroscopic mid‐infrared (MIR) on‐chip sensing. However, detection of gases using on‐chip waveguides (WGs) is challenging because of the low concentrations of gas molecules within the evanescent field surrounding the WGs. To solve this issue, high‐surface‐area, precisely‐controlled‐thickness nanocoatings are introduced whose surface modification with strategically selected silanes enables control of preferential adsorption and concentration of polar versus nonpolar gas analytes. Conformal nanocoatings are constructed using layer‐by‐layer deposition of mesoporous silica nanoparticles (MSNs) at substrate withdrawal speeds controlled within the capillary regime. Surface modification of the WG‐immobilized MSNs with hydrophobic triethoxy(octyl)silane enables, for the first time, enhanced sensitivity and selectivity towards nonpolar methane gas as compared to its polar counterpart acetone. On the other hand, modification of the nanocoatings with (3‐aminopropyl)triethoxysilane leads to preferential binding of polar acetone vapors. This work demonstrates the capability of interfacial modification for controlling the selection and enhancement of the spectroscopic features of gas analytes with different polarities. The developed interfacial assemblies can enable diverse spectroscopic gas sensing platforms for applications in health diagnostics, environmental monitoring, and process control.

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“…Among them, chromatography–mass spectroscopy (GC‐Mass) is a well‐established method in clinical trials for monitoring EBM, owing to its outstanding precision and selectivity (Wang & Sahay, 2009). However, GC‐Mass application often is limited to laboratory usage due to requiring sophisticated, bulky and high‐cost instruments, and experts (Glockler et al, 2020). To date, the advances in portable gas sensors with the miniaturized size hold great potential to overcome such shortcomings and pave the way for point‐of‐care EBM monitoring.…”

Section: Introductionmentioning

confidence: 99%

Metal oxide‐based gas sensors for the detection of exhaled breath markers

2021

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Exhaled breath test is a typical disease monitoring method for replacing of blood and urine samples that may create discomfort for patients. To monitor exhaled breath markers, gas biomedical sensors have undergone rapid progresses for non‐invasive and point‐of‐care diagnostic devices. Among gas sensors, metal oxide‐based biomedical gas sensors have received remarkable attentions owing to their unique properties, such as high sensitivity, simple fabrication, miniaturization, portability, and real‐time monitoring. Herein, we reviewed the recent advances in chemoresistive metal oxide‐based gas sensors with ZnO, SnO 2 , and In 2 O 3 as sensing materials for monitoring a range of exhaled breath markers (i.e., NO, H 2 , H 2 S, acetone, isoprene, and formaldehyde). We focused on the strategies that improve the sensitivity and selectivity of metal oxide‐based gas sensors. The challenges to fabricate a functional gas sensor with high sensing performance along with suggestions are outlined.

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iHWG-MOX: A Hybrid Breath Analysis System via the Combination of Substrate-Integrated Hollow Waveguide Infrared Spectroscopy with Metal Oxide Gas Sensors

Cited by 20 publications

References 44 publications

From Light Pipes to Substrate-Integrated Hollow Waveguides for Gas Sensing: A Review

From Light Pipes to Substrate-Integrated Hollow Waveguides for Gas Sensing: A Review

Silane‐Modified Mesoporous Silica Nanocoatings for Selective Mid‐Infrared Waveguide‐Based Gas Sensing

Metal oxide‐based gas sensors for the detection of exhaled breath markers

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