Exhaled breath contains small molecules and complex volatile organic compounds (VOCs) such as H2O, CO2, NO, NH3, ketones, aldehydes, alcohols, and hydrocarbons. Analysis of VOCs can provide valuabl...

Breath analysis for the screening and diagnosis of diseases

Cardiovascular diseases (CVD) are the major causative factors for high mortality and morbidity in developing and developed nations. The biomarker detection plays a crucial role in the early diagnosis of several non-infectious and life-threatening diseases like CVD and many cancers, which in turn will help in more successful therapy, reducing the mortality rate. Biomarkers have diagnostic, prognostic and therapeutic significances. The search for novel biomarkers using proteomics, bio-sensing, micro-fluidics, and spectroscopic techniques with good sensitivity and specificity for CVD is progressing rapidly at present, in addition to the use of gold standard biomarkers like troponin. This review is dealing with the current progress and prospects in biomarker research for the diagnosis of cardiovascular diseases. Expert opinion. Fast diagnosis of cardiovascular diseases (CVDs) can help to provide rapid medical intervention, which can affect the patient's short and long-term health. Identification and detection of proper biomarkers for early diagnosis are crucial for successful therapy and prognosis of CVDs. The present review discusses the analysis of clinical samples such as whole blood, blood serum, and other body fluids using techniques like high-performance liquid chromatography-LASER/LED-induced fluorescence, Raman spectroscopy, mainly, optical methods, combined with nanotechnology and micro-fluidic technologies, to probe patterns of multiple markers (marker signatures) as compared to conventional techniques. 

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Cardiovascular biomarkers in body fluids: progress and prospects in optical sensors

ABSTRACT Introduction Fiber optic probe-based in vivo spectroscopy techniques are fast and highly objective methods for intraoperative diagnoses and minimally invasive surgical interventions for all procedures where endoscopic observations are carried out for cancers of different types. The Raman spectral features provide molecular fingerprint-type information and can reveal the subjects’ pathological state in label-free manner, making endoscopy multiplexed fiber optic probe-based devices with the potential for translation from bench to bedside for routine applications. Areas Covered This review provides a general overview of different fiber-optic probes for in vivo measurements with emphasis on Raman spectroscopy for biomedical application. Various aspects such as fiber-optic probe, radiation source, detector, and spectrometer for extracting optimum spectral features have also been discussed. Expert opinion Optical spectroscopy-based fiber probe systems with ‘Chip-on-Tip’ technology, combined with machine learning, can in the near future, become a complementary diagnostic tool to magnetic resonance imaging (MRI), computed tomography (CT) scan, ultrasound, etc. Hyperspectral imaging and fluorescence-based devices are in the advanced stage of technology readiness level (TRL), and with advances in lasers and miniature spectroscopy systems, probe-based Raman devices are also coming up.

In vivo spectroscopy: optical fiber probes for clinical applications

Research activities are in full swing globally to translate the use of saliva as a non-invasive and highly potential specimen for clinical diagnostics, particularly for COVID-19 detection. Being comprised of a pool of biomarkers also enriched with ACE-2 receptors, saliva can provide vital information regarding the state of the human body. Advancements in biophotonics tools for saliva investigation may offer promise for developing rapid, highly objective, optical modalities for COVID- 19 detection. This article presents concept/design study, which propose the use of Raman/laser induced fluorescence spectroscopic device that have the potential for viral detection via saliva from a safer distance. Noticeable changes of biomarkers present in saliva in response to viral infection can reflect the pathological state, thus can altogether affect the Raman spectral pattern. Monitoring these spectral patterns of saliva, which are further enhanced by using cost effective and reproducible Surface Enhanced Raman Spectroscopy substrates can be a viable option for sensitive and non-invasive viral detection. The spectral information acquired from the optical device can be processed using various multivariate statistical analytical tools, which ultimately facilitate effective viral detection in few minutes. This method doesn't demand the necessity of qualified professionals and sample processing with reagents unlike in RT-PCR test. The proposed optical device can be further modified into a portable form, which can be easily transported for field applications. The stand-off observation, contactless and highly non-invasive technique can be of paramount importance in the current context, where the safer screening of a large population for viral infection by maintaining social distances is a necessity. The proposed stand-off spectroscopic technique can also address the major concern of nosocomial viral transmission amongst healthcare workers during sample collection in a pandemic scenario.

Development of a spectroscopic technique that enables the saliva based detection of COVID-19 at safe distances.

Radiotherapy remains one of the major treatment modalities for cancer even though it is known to produce serious immediate, early-delayed and late delayed side effects. A study of biochemical processes taking place in the system following radiation therapy will be very important in understanding these effects. Spectroscopic methods provide very sensitive techniques for identification and determination of individual components in complex biological samples. Its applications in clinical diagnostics, both in-vitro and in-vivo, are being explored very vigorously at present. Effects of radiation exposure on living systems have been studied by several groups in the past. However, all such studies have been based on morphological and histopathological analyses which cannot usually give information on immediate or early delayed damages and many of the biochemical changes causing such damages. Practically no spectroscopic studies have been carried out in this area so far, in spite of the fact that information at a molecular level can be obtained by such studies at various stages after radiation exposure. This article describes the potential of laser Raman, fluorescence, and proteomics spectroscopy techniques for the evaluation of immediate, early-delayed and late-delayed radiation effects in mouse models and human systems. Techniques of Time-Delayed spectroscopy, Principal Component Analysis, and curve-fitting of spectra are used in interpretation of the complex spectral changes observed in trauma, administration of drugs and radiation exposure.

Laser spectroscopy studies of radiation effects on animal models and human systems

In this paper the potential of optical spectroscopy based techniques for regular screening and early diagnosis of “Killer” diseases (various types of cancers, cardiovascular diseases, etc.) is discussed with focus on routine use under low-resource settings. A brief account of work carried out in our laboratory to design, assemble and optimize Laser Induced Fluorescence (LIF) based optical devices for routine screening, early diagnosis and discrimination of premalignant/malignant conditions in oral and other cancers is presented. An ultra-sensitive protein profiling system based on highly efficient High Performance Liquid Chromatograpy-Ultrasensitive Laser Induced Fluorescence (HPLC-LIF) detection, and its extensive use in monitoring various cancers, coronary conditions, gynecological problems etc. through protein profile pattern analyses of markers in body fluids is also discussed.

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Swathi Rao

Papers

Optical biopsy and optical pathology: Affordable health care under low-resource settings