Systematic approaches for biodiagnostics using exhaled air

Electrochemical Detection of Gasotransmitters: Status and Roadmap

Gasotransmitters, including nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S), are a class of gaseous, endogenous signaling molecules that interact with one another in the regulation of critical cardiovascular, immune, and neurological processes. The development of analytical sensing mechanisms for gasotransmitters, especially multianalyte mechanisms, holds vast importance and constitutes a growing area of study. This review provides an overview of electrochemical sensing mechanisms with an emphasis on opportunities in multianalyte sensing. Electrochemical methods demonstrate good sensitivity, adequate selectivity, and the most well-developed potential for the multianalyte detection of gasotransmitters. Future research will likely address challenges with sensor stability and biocompatibility (i.e., sensor lifetime and cytotoxicity), sensor miniaturization, and multianalyte detection in biological settings.

Ceria-Based Nanozymes in Point-of-Care Diagnosis: An Emerging Futuristic Approach for Biosensing

In recent years, there has been a notable increase in interest surrounding nanozymes due to their ability to imitate the functions and address the limitations of natural enzymes. The scientific community has been greatly intrigued by the study of nanoceria, primarily because of their distinctive physicochemical characteristics, which include a variety of enzyme-like activities, affordability, exceptional stability, and the ability to easily modify their surfaces. Consequently, nanoceria have found extensive use in various biosensing applications. However, the impact of its redox activity on the enzymatic catalytic mechanism remains a subject of debate, as conflicting findings in the literature have presented both pro-oxidant and antioxidant effects. Herein, we creatively propose a seesaw model to clarify the regulatory mechanism on redox balance and survey possible mechanisms of multienzyme mimetic properties of nanoceria. In addition, this review aims to showcase the latest advancements in this field by systematically discussing over 180 research articles elucidating the significance of ceria-based nanozymes in enhancing, downsizing, and enhancing the efficacy of point-of-care (POC) diagnostics. These advancements align with the ASSURED criteria established by the World Health Organization (WHO). Furthermore, this review also examines potential constraints in order to offer readers a concise overview of the emerging role of nanoceria in the advancement of POC diagnostic systems for future biosensing applications.

Moderate body lipid accumulation in mice attenuated benzene-induced hematotoxicity via acceleration of benzene metabolism and clearance

Recent population and animal studies have revealed a correlation between fat content and the severity of benzene-induced hematologic toxicity. However, the precise impact of lipid deposition on benzene-induced hematotoxicity and the underlying mechanisms remain unclear. In this study, we established a mouse model with moderate lipid accumulation by subjecting the mice to an 8-week high-fat diet (45% kcal from fat, HFD), followed by 28-day inhalation of benzene at doses of 0, 1, 10, and 100 ppm. The results showed that benzene exposure caused a dose-dependent reduction of peripheral white blood cell (WBC) counts in both diet groups. Notably, this reduction was less pronounced in the HFD-fed mice, suggesting that moderate lipid accumulation mitigates benzene-related hematotoxicity. To investigate the molecular basis for this effect, we performed bioinformatics analysis of high-throughput transcriptome sequencing data, which revealed that moderate lipid deposition alters mouse metabolism and stress tolerance towards xenobiotics. Consistently, the expression of key metabolic enzymes, such as Cyp2e1 and Gsta1, were upregulated in the HFD-fed mice upon benzene exposure. Furthermore, we utilized a real-time exhaled breath detection technique to monitor exhaled benzene metabolites, and the results indicated that moderate lipid deposition enhanced metabolic activation and increased the elimination of benzene metabolites. Collectively, these findings demonstrate that moderate lipid deposition confers reduced susceptibility to benzene-induced hematotoxicity in mice, at least in part, by accelerating benzene metabolism and clearance.

Online mass spectrometry of exhaled breath with a modified ambient ion source

Exhaled breath (EB) may contain metabolites that are closely related to human health conditions. Real time analysis of EB is important to study its true composition, however, it has been difficult. A robust ambient ionization mass spectrometry method using a modified direct analysis in real time (DART) ion source was developed for the online analysis of breath volatiles. The modified DART ion source can provide a confined region for direct sampling, rapid transmission and efficient ionization of exhaled breath. With different sampling methods, offline analysis and near real-time evaluation of exhaled breath were also achieved, and their unique molecular features were characterized. High resolution MS data aided the putative metabolite identification in breath samples, resulting in hundreds of volatile organic compounds being identified in the exhalome. The method was sensitive enough to be used for monitoring the breath feature changes after taking different food and over-the-counter medicine. Quantification was performed for pyridine and valeric acid with fasting and after ingesting different food. The developed method is fast, simple, versatile, and potentially useful for evaluating the true state of human exhaled breath.

Qualitative and quantitative determination of butanol in latex paint by fast gas chromatography proton transfer reaction mass spectrometry

Butanol is a common organic solvent used in latex paint, and one of its isomers, tert-butanol, is toxic and can cause potential harm to the human body. Therefore, it is of great significance to develop a qualitative and quantitative detection method for butanol isomers. In this study, we combined the advantages of rapid detection of proton transfer reaction mass spectrometry (PTR-MS) with the separation and qualitative capabilities of gas chromatography-mass spectrometry (GC-MS) to achieve the detection of isomers, building a fast gas chromatography proton transfer reaction mass spectrometry (FastGC-PTR-MS) equipment. Firstly, the developed technology was optimized using standard samples of several common volatile organic compounds. The retention times of acetonitrile, acetone, and alcohols were less than 50 s, and the retention times of the benzene series were less than 110 s, on the premise that these isomers could be basically separated (resolution R > 1.0). Compared with a commercial GC-MS equipment, the detection times were shortened by 5-6 times and 2-4 times, respectively. Then the FastGC-PTR-MS was applied to detect the isomers of butanol in latex paint. The results showed that the headspace of brand D latex paint mainly contained five substances: tert-butanol, n-butanol, acetaldehyde, methanol, and acetone. Tert-butanol and n-butanol could be completely separated (R > 1.5). The concentration of tert-butanol was 4.41 ppmv, far below the 100 ppmv maximum allowable workplace concentration. The developed FastGC-PTR-MS can be used for rapid qualitative and quantitative detection of butanol isomers in latex paint. The new equipment has the potential to play an important role in indoor environmental safety applications.

Diversified applications of self-assembled nanocluster delivery systems- A state-of-the- art review

BACKGROUND

Self-assembled nanoclusters arrange the components into an organized structure for the nanoparticulate system and also in the transportation of cellular elements for the fabrication of microelectronic devices. Nanoclusters reduce transcytosis and increase endocytosis in intestinal mucin to strengthen the retrograde pathway that helped in the delivery of actives to the Golgi apparatus.

OBJECTIVES

This review article focuses on the self-assembled nanoclusters for cellular transportation, applications of self-assembled structures in the delivery of essential elements like the use of a peptide in targeted and stimuli-responsive drug delivery systems, self-assembly of tocopherol nanoclusters that promotes vitamin E delivery across the endothelial barrier. Methods Current innovation in the self-assembly of peptides includes the formation of nanostructures like vesicles, fibers, and rod-coil in the applications of wound healing, tissue engineering, treatment of atherosclerosis, in sensing heavy metals from biological and environmental samples and advanced drug delivery.

RESULTS

Self-assembled biodegradable nanoclusters are used as biomimetic structures for synergistic effect. Improvement in the methods of preparation like the addition of a copolymer is used for temperature-triggered drug release nanoclusters.

CONCLUSION

Green synthesis of nanoclusters, nanocluster-based biosensor and artificial intelligence are the future concept in the manufacturing and the prevention of toxicity in humans.

Detection of SARS-CoV-2 infection by exhaled breath spectral analysis: Introducing a ready-to-use point-of-care mass screening method

BACKGROUND

The current SARS-CoV-2 pandemic created an urgent need for rapid, infection screening applied to large numbers of asymptomatic individuals. To date, nasal/throat swab polymerase chain reaction (PCR) is considered the "gold standard". However, this is inconducive to mass, point-of-care (POC) testing due to person discomfort during sampling and a prolonged result turnaround. Breath testing for disease specific organic compounds potentially offers a practical, rapid, non-invasive, POC solution. The study compares the Breath of Health, Ltd. (BOH) breath analysis system to PCR's ability to screen asymptomatic individuals for SARS-CoV-2 infection. The BOH system is mobile and combines Fourier-transform infrared (FTIR) spectroscopy with artificial intelligence (AI) to generate results within 2 min and 15 s. In contrast to prior SARS-CoV-2 breath analysis research, this study focuses on diagnosing SARS-CoV-2 via disease specific spectrometric profiles rather than through identifying the disease specific molecules.

METHODS

Asymptomatic emergency room patients with suspected SARS-CoV-2 exposure in two leading Israeli hospitals were selected between February through April 2021. All were tested via nasal/throat-swab PCR and BOH breath analysis. In total, 297 patients were sampled (mean age 57·08 ± SD 18·86, 156 males, 139 females, 2 unknowns). Of these, 96 were PCR-positive (44 males, 50 females, 2 unknowns), 201 were PCR-negative (112 males, 89 females). One hundred samples were used for AI identification of SARS-CoV-2 distinguishing spectroscopic wave-number patterns and diagnostic algorithm creation. Algorithm validation was tested in 100 proof-of-concept samples (34 PCR-positive, 66 PCR-negative) by comparing PCR with AI algorithm-based breath-test results determined by a blinded medical expert. One hundred additional samples (12 true PCR-positive, 85 true PCR-negative, 3 confounder false PCR-positive [not included in the 297 total samples]) were evaluated by two blinded medical experts for further algorithm validation and inter-expert correlation.

FINDINGS

The BOH system identified three distinguishing wave numbers for SARS-CoV-2 infection. In the first phase, the single expert identified the first 100 samples correctly, yielding a 1:1 FTIR/AI:PCR correlation. The two-expert second-phase also yielded 1:1 FTIR/AI:PCR correlation for 97 non-confounders and null correlation for the 3 confounders. Inter-expert correlation was 1:1 for all results. In total, the FTIR/AI algorithm demonstrated 100% sensitivity and specificity for SARS-CoV-2 detection when compared with PCR.

INTERPRETATION

The SARS-CoV-2 method of breath analysis via FTIR with AI-based algorithm demonstrated high PCR correlation in screening for asymptomatic individuals. This is the first practical, rapid, POC breath analysis solution with such high PCR correlation in asymptomatic individuals. Further validation is required with a larger sample size.

FUNDING

Breath of Health Ltd, Rehovot, Israel provided study funding.

Research Progress of Graphene and Its Derivatives towards Exhaled Breath Analysis

The metabolic process of the human body produces a large number of gaseous biomarkers. The tracking and monitoring of certain diseases can be achieved through the detection of these markers. Due to the superior specific surface area, large functional groups, good optical transparency, conductivity and interlayer spacing, graphene, and its derivatives are widely used in gas sensing. Herein, the development of graphene and its derivatives in gas-phase biomarker detection was reviewed in terms of the detection principle and the latest detection methods and applications in several common gases, etc. Finally, we summarized the commonly used materials, preparation methods, response mechanisms for NO, NH₃, H₂S, and volatile organic gas VOCs, and other gas detection, and proposed the challenges and prospective applications in this field.

Adsorption of cisplatin on oxidized graphene nanoribbons for improving the uptake in non-small cell lung carcinoma cell line A549

BACKGROUND

Graphene nanoribbons are nanosized strips of graphene with unique physicochemical properties like higher drug loading capacity and affinity for tumor cells.

OBJECTIVE

The principal objective of this research was to develop oxidized graphene nanoribbons (O-GNRs)-a based delivery system for cisplatin against non-small cell lung carcinoma cell line A549 by selective endocytosis.

METHOD

The O-GNRs prepared using various synthetic steps like oxidative unzipping were evaluated for various parameters like morphology, Fourier Transform Infrared (FTIR) study, % adsorption efficacy, Differential scanning colometric (DSC) study, and in-vitro efficacy studies.

RESULTS

Graphene nanoribbons with the length of 200-250 nm and width of 20-40 nm were obtained. The FTIR spectrum of drug-loaded O-GNRs exhibited a characteristic peak at 1550 cm-1 (-N-H group) of cisplatin. The DSC indicated the presence of sharp endothermic peaks at 59 ºC (PEG), 254 ºC (-C-NH3) and 308.6 ºC (-C-Pt). The % adsorption efficiency was found to be 74.56 ± 0.798% with in-vitro release in controlled manner (63.36 % ± 0.489 %) for 24 h.

CONCLUSION

The nanoformulation showed an average inhibition of 22.72% at a lower dose of cisplatin (> 25%) by passive targeting cell line A549 by DNA alkylation. In the near future, graphene-based systems will establish potential nanosystems in cancer treatment due to the additive effect of graphene with various therapeutic agents.

Induced volatolomics of pathologies

Volatolomics allows us to elucidate cell metabolic processes in real time. In particular, a volatile organic compound (VOC) excreted from our bodies may be specific for a certain disease, such that measuring this VOC may afford a simple, fast, accessible and safe diagnostic approach. Yet, finding the optimal endogenous volatile marker specific to a pathology is non-trivial because of interlaboratory disparities in sample preparation and analysis, as well as high interindividual variability. These limit the sensitivity and specificity of volatolomics and its applications in biological and clinical fields but have motivated the development of induced volatolomics. This approach aims to overcome issues by measuring VOCs that result not from an endogenous metabolite but, rather, from the pathogen-specific or metabolic-specific enzymatic metabolism of an exogenous biological or chemical probe. In this Review, we introduce volatile-compound-based probes and discuss how they can be exploited to detect and discriminate pathogenic infections, to assess organ function and to diagnose and monitor cancers in real time. We focus on cases in which labelled probes have informed us about metabolic processes and consider the potential and drawbacks of the probes for clinical trials. Beyond diagnostics, VOC-based probes may also be effective tools to explore biological processes more generally.

Applications of Near Infrared Photoacoustic Spectroscopy for Analysis of Human Respiration: A Review

In this review, applications of near-infrared photoacoustic spectroscopy are presented as an opportunity to evaluate human respiration because the measurement of breath is fast, intact and simple to implement. Recently, analytical methods for measuring biomarkers in exhaled air have been extensively developed. With laser-based photoacoustic spectroscopy, volatile organic compounds can be identified with high sensitivity, at a high rate, and with very good selectivity. The literature review has shown the applicability of near-infrared photoacoustic spectroscopy to one of the problems of the real world, i.e., human health. In addition, the review will consider and explore different breath sampling methods for human respiration analysis.

Non-invasive Biodiversified Sensors: A Modernized Screening Technology for Cancer

Background:

Biological sensors revolutionize the method of diagnoses of diseases from early to final stages using the biomarkers present in the body. Biosensors are advantageous due to the involvement of minimal sample collection with improved specificity and sensitivity for the detection of biomarkers.

Methods:

Conventional biopsies restrict problems like patient non-compliance, cross-infection and high cost and to overcome these issues biological samples like saliva, sweat, urine, tears and sputum progress into clinical and diagnostic research for the development of non-invasive biosensors. This article covers various non-invasive measurements of biological samples, optical-based, mass-based, wearable and smartphone-based biosensors for the detection of cancer.

Results:

The demand for non-invasive, rapid and economic analysis techniques escalated due to the modernization of the introduction of self-diagnostics and miniature forms of devices. Biosensors have high sensitivity and specificity for whole cells, microorganisms, enzymes, antibodies, and genetic materials.

Conclusion:

Biosensors provide a reliable early diagnosis of cancer, which results in faster therapeutic outcomes with in-depth fundamental understanding of the disease progression.

Bio-inspired nano-engineered strip for semiquantitative FeNO analysis

A point-of-care, non-invasive, low-cost and sensitive nano-biodiagnostic is needed in today's age for rapid and accurate self-diagnosis as well as for the management of asthma, which is advantageous for low resource areas where asthma is prevalent. The objective of this research work was to prepare the miniature, nanosponges coated paper strip to detect the asthma using certain biomarkers present in exhaled air. The asthma biomarker, nitric oxide present in exhaled air (FeNO) was chosen, which on reaction with nanosponges of diazotizing agent gave significant color change. The pyromellitic anhydride cross-linked β-cyclodextrin-based nanosponges of sulfanilamide and N-(1-naphthyl) ethylenediamine dihydrochloride were prepared using a polymer condensation method and coated on Whatman filter paper strip (1 × 5 cm2). The thickness of coating was found to be uniform (400 ± 50 μm) which was determined using SEM analysis. The Hue-Saturation-Value scale was used to detect the color change using a smartphone app. We also investigated the performance of a nano-engineered paper strip by comparing this with commercially available, FDA approved FeNO analyzer-NIOX MINO. Our findings demonstrated no significant difference in results obtained using both the techniques. Besides good repeatability, the paper strip showed increasing saturation with NO concentration and the capacity to detect the biomarker down to mean value of 20.33 ppb level. The successful validation and method comparison indicated that a bioinspired strip can provide on-site analysis and daily monitoring for diagnosis and management of asthma.

Breath analysis as a diagnostic and screening tool for malignant pleural mesothelioma: a systematic review

Malignant pleural mesothelioma (MPM) is a tumour related to a historical exposure to asbestos fibres. Currently, the definite diagnosis is made only by the histological examination of a biopsy obtained through an invasive thoracoscopy. However, diagnosis is made too late for curative treatment because of non-specific symptoms mainly appearing at advanced stage disease. Hence, due to its biologic aggressiveness and the late diagnosis, survival rate is low and the patients' outcome poor. In addition, radiological imaging, like computed tomographic scans, and blood biomarkers are found not to be sensitive enough to be used as an early diagnostic tool. Detection in an early stage is assumed to improve the patients' outcome but is hampered due to non-specific and late symptomology. Hence, there is a need for a new screening and diagnostic test which could improve the patients' outcome. Despite extensive research has focused on blood biomarkers, not a single has been shown clinically useful, and therefore research recently shifted to "breathomics" techniques to recognize specific volatile organic compounds (VOCs) in the breath of the patient as potential non-invasive biomarkers for disease. In this review, we summarize the acquired knowledge about using breath analysis for diagnosing and monitoring MPM and asbestos-related disorders (ARD). Gas chromatography-mass spectrometry (GC-MS), the gold standard of breath analysis, appears to be the method with the highest accuracy (97%) to differentiate MPM patients from at risk asbestos-exposed subjects. There have already been found some interesting biomarkers that are significantly elevated in asbestosis (NO, 8-isoprostane, leukotriene B4, α-Pinene…) and MPM (cyclohexane) patients. Regrettably, the different techniques and the plethora of studies suffer some limitations. Most studies are pilot studies with the inclusion of a limited number of patients. Nevertheless, given the promising results and easy sampling methods, we can conclude that breath analysis may become a useful tool in the future to screen for MPM, but further research is warranted.