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Heart failure (HF) is the main cause of mortality worldwide, particularly in the elderly. N-terminal pro-brain natriuretic peptide (NT-proBNP) is the gold standard biomarker for HF diagnosis and therapy monitoring. It is determined in blood samples by the immunochemical methods generally adopted by most laboratories. Saliva analysis is a powerful tool for clinical applications, mainly due to its non-invasive and less risky sampling. This study describes a validated analytical procedure for NT-proBNP determination in saliva samples using a commercial Enzyme-Linked Immuno-Sorbent Assay. Linearity, matrix effect, sensitivity, recovery and assay-precision were evaluated. The analytical approach showed a linear behaviour of the signal throughout the concentrations tested, with a minimum detectable dose of 1 pg/mL, a satisfactory NT-proBNP recovery (95–110%), and acceptable precision (coefficient of variation ≤ 10%). Short-term (3 weeks) and long-term (5 months) stability of NT-proBNP in saliva samples under the storage conditions most frequently used in clinical laboratories (4, − 20, and − 80 °C) was also investigated and showed that the optimal storage conditions were at − 20 °C for up to 2.5 months. Finally, the method was tested for the determination of NT-proBNP in saliva samples collected from ten hospitalized acute HF patients. Preliminary results indicate a decrease in NT-proBNP in saliva from admission to discharge, thus suggesting that this procedure is an effective saliva-based point-of-care device for HF monitoring.

Heart failure (HF) is a chronic cardiovascular disease that represents main cause of mortality worldwide, particularly for elderly. N-terminal pro-brain natriuretic peptide (NT-proBNP) was identified as the gold standard biomarker for HF diagnosis and therapy monitoring. Presently, saliva analysis represents an emerging and powerful tool for clinical applications and electrochemical immunosensors have shown their potential in Healthcare applications as selective and reliable systems for detecting clinical biomarkers. This work presents the detection of NT-proBNP in saliva samples by an immunologically modified Field effect Transistor (IMFET). TESUD ((11-triethoxysilyl) undecanal) was used as cross-linker to immobilise anti-NT-proBNP antibody onto the device. Our IMFET that was then tested in different matrices (e.g. phosphate buffered saline (PBS), artificial saliva and human saliva) using electrochemical impedance spectroscopy (EIS), and it resulted selective to NT-proBNP with good sensitivity (detection limit of 0.02 pg/mL) and a wide linear range (0.02-1 pg/mL and 0.5-20 pg/mL). Finally, NT-proBNP concentration in ten saliva samples was determined by performing the standard addition method. An enzyme-linked immunosorbent assay was used for confirming IMFET results, highlighting both IMFET accuracy (analyte recovery of 99 ± 8%) and precision (coefficient of variation always10%), and supporting the suitability of the device for determining salivary NT-proBNP.

When working with humid gaseous samples, the amount of water vapour collected in a needle trap along with volatile analytes may vary from sample to sample and decrease during the storage. This has a major impact on desorption efficiency and recovery. We propose the addition of a labelled internal standards to nullify the effect of variable humidity on the analytical performance of needle trap micro-extraction combined with gas chromatography mass spectrometry. Triple-bed (Divinylbenzene/Carbopack X/Carboxen 1000) and single-bed (Tenax GR) needles were tested with standard gaseous mixtures prepared at different relative humidity levels (85%, 50% and 10%). The standard mixtures contained twenty-five analytes representative of breath and ambient air constituents, including hydrocarbons, ketones, aldehydes, aromatics, and sulphurs, in the concentration range 0.1-700 ppbv. The two needles showed different behaviours, as recovery was independent of humidity for single-beds, whereas a low recovery (10-20%) was observed when triple-beds trapped very volatile compounds at low humidity (e.g. pentane and ethanol, 10% relative humidity. Triple-beds showed an almost quantitative recovery (>90%) of all the analytes at 50% and 85% relative humidity. This big difference was probably due to the reduced action of water vapour pressure during the desorption step. The addition of 6 D-acetone and 8 D-toluene to the sorbent material before gas sampling and the normalization of raw data nullified this effect, thereby lowering the variations of analyte recovery at different humidity levels down to 20%. Internal standards were also exploited to limit within 10-20% alterations in peak areas of very volatile compounds during needle storage at room temperature. This variation may results from a loss of water vapour either retained from the sorbent material and/or condensed on triple-bed needle walls. After normalization, the inter- and intra-day precision were halved to 5% and 10% in the case of single-beds, respectively, and to 15% and 20% with three-beds. The addition of an internal standard to the sorbent helps to keep the overall analytical procedure under control and improves the reliability of needle trap micro-extraction for the analysis of volatile organic compounds at ultra-trace levels.

International audience; According to the European statistics, approximately 26 million patients worldwide suffer from heart failure (HF), and this number seems to be steadily increasing. Inflammation plays a central role in the development of HF, and the pro-inflammatory cytokine Tumor necrosis factor-α (TNF-α) represents inflammation gold-standard biomarker. Early detection plays a crucial role for the prognosis and treatment of HF. An Ion Sensitive Field Effect Transistor (ISFET) based on silicon nitride transducer and biofunctionalized with anti-TNF-α antibody for label-free detection of salivary TNF-α is proposed. Electrochemical impedance spectroscopy (EIS) was used for TNF-α detection. Our ImmunoFET offered a detection limit of 1 pg mL−1, with an analytical reproducibility expressed by a coefficient of variance (CV) resulted < 10% for the analysis of saliva samples, and an analyte recovery of 94 ± 6%. In addition, it demonstrated high selectivity when compared to other HF biomarkers such as Inteleukin-10, N-terminal pro B-type natriuretic peptide, and Cortisol. Finally, ImmunoFET accuracy in determining the unknown concentration of TNF-α was successfully tested in saliva samples by performing standard addition method. The proposed ImmunoFET showed great promise as a complementary tool for biomedical application for HF monitoring by a non-invasive, rapid and accurate assessment of TNF-α.

Breath analysis is an alternative approach for disease diagnosis and for monitoring therapy. The lack of standardized procedures for collecting and analysing breath samples currently limits its use in clinical practice. In order to overcome this limitation, the ‘Peppermint Consortium’ was established within the breath community to carry out breath wash-out experiments and define reference values for a panel of compounds contained in the peppermint oil capsule. Here, we present a needle trap micro-extraction technique coupled with gas chromatography and tandem mass spectrometry for a rapid and accurate determination of alpha-pinene, beta-pinene, limonene, eucalyptol, menthofuran, menthone, menthol and menthyl acetate in mixed breath samples. Detection limits between 1 and 20 pptv were observed when 25 ml of a humidified standard gas mixture were loaded into a needle trap device at a flow rate of 10 ml min−1. Inter- and intra-day precisions were lower than 15%, thus confirming the reliability of the assay. Our procedure was used to analyse breath samples taken from a nominally healthy volunteer who was invited to swallow a 200 mg capsule of peppermint oil. Six samples were collected at various times within 6 h of ingestion. Analyte concentrations were not affected by the sampling mode (i.e. mixed vs. end-tidal fraction), whereas respiratory rate and exhalation flow rate values slightly influenced the concentration of the target compounds in breath samples.

International audience; The aim of this study was to perform a systematic review on the potential value of saliva biomarkers in the diagnosis, management and prognosis of heart failure (HF). The correlation between saliva and plasma values of these biomarkers was also studied. PubMed was searched to collect relevant literature, i.e., case-control, cross-sectional studies that either compared the values of salivary biomarkers among healthy subjects and HF patients, or investigated their role in risk stratification and prognosis in HF patients. No randomized control trials were included. The search ended on 31st of December 2020. A total of 15 studies met the inclusion criteria. 18 salivary biomarkers were analyzed and the levels of all biomarkers studied were found to be higher in HF patients compared to controls, except for amylase, sodium, and chloride that had smaller saliva concentrations in HF patients. Natriuretic peptides are the most commonly used plasma biomarkers in the management of HF. Their saliva levels show promising results, although the correlation of saliva to plasma values is weakened in higher plasma values. In most of the publications, differences in biomarker levels between HF patients and controls were found to be statistically significant. Due to the small number of patients included, larger studies need to be conducted in order to facilitate the use of saliva biomarkers in clinical practice.

Mostly known as “the stress hormone”, cortisol has many essential functions in humans due to its involvement in regulation of blood pressure, immune system, metabolism of protein, carbohydrate, adipose, and anti-inflammatory action. Since a right cortisol balance is essential for human health, many efforts are currently being made to monitor the cortisol level in the human body. Cortisol levels are usually monitored in blood, plasma, serum, oral fluid, sweat, and hair samples through immunochemical and analytical methods, but in the last decade, electrochemical measurements are proving to be reliable techniques for cortisol quantification in biological matrices with the advantages of a fast response by portable and wearable devices. This review gathers the most recent developments and works on electrochemical sensors for cortisol detection, highlighting their high technology maturity and potential for clinical applications.

Lymphocytes (B, T and natural killer cells) and immunoglobulins are essential for the adaptive immune response against external pathogens. Flow cytometry and enzyme-linked immunosorbent (ELISA) kits are the gold standards to detect immunoglobulins, B cells and T cells, whereas the impedance measurement is the most used technique for natural killer cells. For point-of-care, fast and low-cost devices, biosensors could be suitable for the reliable, stable and reproducible detection of immunoglobulins and lymphocytes. In the literature, such biosensors are commonly fabricated using antibodies, aptamers, proteins and nanomaterials, whereas electrochemical, optical and piezoelectric techniques are used for detection. This review describes how these measurement techniques and transducers can be used to fabricate biosensors for detecting lymphocytes and the total content of immunoglobulins. The various methods and configurations are reported, along with the advantages and current limitations.

A new series of sidewall modified single-walled carbon nanotubes (SWCNTs) with perfluorophenyl molecules bearing carboxylic acid or methyl ester moieties are herein reported. Pristine and functionalized SWCNTs (p-SWCNTs and f-SWCNTs, respectively) were characterized by X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and scanning electron microscopy (SEM). The nitrene-based functionalization provided intact SWCNTs with methyl 4-azido-2,3,5,6-tetrafluorobenzoate (SWCNT-N-C(6)F(4)CO(2)CH(3)) and 4-azido-2,3,5,6-tetrafluorobenzoic acid (SWCNT-N-C(6)F(4)CO(2)H) attached every 213 and 109 carbon atoms, respectively. Notably, SWCNT-N-C(6)F(4)CO(2)H was sensitive in terms of the percentage of conductance variation from 5 to 40 ppm of ammonia (NH(3)) and trimethylamine (TMA) with a two-fold higher variation of conductance compared to p-SWCNTs at 40 ppm. The sensors are highly sensitive to NH(3) and TMA as they showed very low responses (0.1%) toward 200 ppm of volatile organic compounds (VOCs) containing various functional groups representative of different classes of analytes such as benzene, tetrahydrofurane (THF), hexane, ethyl acetate (AcOEt), ethanol, acetonitrile (CH(3)CN), acetone and chloroform (CHCl(3)). Our system is a promising candidate for the realization of single-use chemiresistive sensors for the detection of threshold crossing by low concentrations of gaseous NH(3) and TMA at room temperature.

Heart failure (HF) is a cardiovascular disease affecting about 26 million people worldwide costing about $100 billons per year. HF activates several compensatory mechanisms and neurohormonal systems, so we hypothesized that the concomitant monitoring of a panel of potential biomarkers related to such conditions might help predicting HF evolution. Saliva analysis by point-of-care devices is expected to become an innovative and powerful monitoring approach since the chemical composition of saliva mirrors that of blood. The aims of this study were (i) to develop an innovative procedure combining MEPS with UHPLC-MS/MS for the simultaneous determination of 8-isoprostaglandin F2α and cortisol in saliva and (ii) to monitor lactate, uric acid, TNF-α, cortisol, α-amylase and 8-isoprostaglandin F2α concentrations in stimulated saliva samples collected from 44 HF patients during their hospitalisation due to acute HF. Limit of detection of 10 pg/mL, satisfactory recovery (95–110%), and good intra- and inter-day precisions (RSD ≤ 10%) were obtained for 8-isoprostaglandin F2α and cortisol. Salivary lactate and 8-isoprostaglandin F2α were strongly correlated with NT-proBNP. Most patients (about 70%) showed a significant decrease (a factor of 3 at least) of both lactate and 8-isoprostaglandin F2α levels at discharge, suggesting a relationship between salivary levels and improved clinical conditions during hospitalization.

Exhaled air and breath condensate contain a large number of health biomarkers, such as volatile and semi-volatile organic compounds, proteins and lipids. Nowadays, the collection of breath samples is carried out by commercial or lab-made sampling systems that collect only one type of sample (e.g. gaseous or condensate phase), thus limiting the diagnostic capability of breath tests. This work presents a portable prototype optimized for the simultaneous collection of gaseous exhaled breath and exhaled breath condensate within five minutes. The system is fully portable and has a total weight of about 1 Kg. An illustrative determination of ethanol, isoprene, acetone, isopropyl alcohol, 1-propanol, 2-butanone, 2-pentanone, toluene and xylenes in breath, and cortisol and 8-iso-prostaglandin F 2α in breath condensate is discussed.

Background: Increasing evidence links meteorological characteristics and air pollution to physiological responses during sports activities in urban areas with different traffic levels. Objective: The main objective of the Smart Healthy ENV (SHE, “Smart Monitoring Integrated System For A Healthy Urban Environment In Smart Cities”) project was to identify the specific responses of a group of volunteers during physical activity, by monitoring their heart rates and collecting breath samples, combined with data on meteorological determinants and pollution substances obtained through fixed sensor nodes placed along city routes and remotely connected to a dedicated data acquisition server. Methods: Monitoring stations were placed along two urban routes in Pisa, each two km long, with one located within the park beside the Arno river (green route) and the other in a crowded traffic zone (red route). Our sample participants were engaged in sports activities (N = 15, with different levels of ability) and were monitored through wearable sensors. They were first asked to walk back and forth (4 km) and then to run the same route. The experimental sessions were conducted over one day per route. A breath sample was also collected before each test. A questionnaire concerning temperature and fatigue perception was administered for all of the steps of the study over the two days. Results: The heart rates of the participants were monitored in the baseline condition, during walking, and while running, and were correlated with meteorological and pollutant data and with breath composition. Changes in the heart rates and breath composition were detected during the experimental sessions. These variations were related to the physical activity and to the meteorological conditions and air pollution levels. Conclusions: The SHE project can be considered a proof-of-concept study aimed at monitoring physiological and environmental variables during physical activity in urban areas, and can be used in future studies to provide useful information to those involved in sports and the broader community.

International audience; Biomarkers of oxidative stress are generally measured in blood and its derivatives. However, the invasiveness of blood collection makes the monitoring of such chemicals during exercise not feasible. Saliva analysis is an interesting approach in sport medicine because the collection procedure is easy-to-use and does not require specially-trained personnel. These features guarantee the collection of multiple samples from the same subject in a short span of time, thus allowing the monitoring of the subject before, during and after physical tests, training or competitions. The aim of this work was to evaluate the possibility of following the changes in the concentration of some oxidative stress markers in saliva samples taken over time by athletes under exercise. To this purpose, ketones (i.e. acetone, 2-butanone and 2-pentanone), aldehydes (i.e. propanal, butanal, and hexanal), α,β-unsaturated aldehydes (i.e. acrolein and methacrolein) and di-carbonyls (i.e. glyoxal and methylglyoxal) were derivatized with 2,4-dinitrophenylhydrazine, and determined by ultra-high performance liquid chromatography coupled to diode array detector. Prostaglandin E2, F2/E2-isoprostanes, F2-dihomo-isoprostanes, F4-neuroprostanes, and F2-dihomo-isofuranes were also determined by a reliable analytical procedure that combines micro-extraction by packed sorbent and ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Overall the validation process showed that the methods have limits of detection in the range of units of ppb for carbonyls and tens to hundreds of ppt for isoprostanes and prostanoids, very good quantitative recoveries (90–110%) and intra- and inter-day precision lower than 15%. The proof of applicability of the proposed analytical approach was investigated by monitoring the selected markers of oxidative stress in ten swimmers performing a VO2max cycle ergo meter test. The results highlighted a clear increase of salivary by-products of oxidative stress during exercise, whereas a sharp decrease, approaching baseline values, of these compounds was observed in the recovery phase. This study opens up a new approach in the evaluation of oxidative stress and its relation to aerobic activity.

In this study, we report the development of a sensitive electrochemical immunosensor for the detection of the tumor necrosis factor-α (TNF-α) cytokine in human saliva samples. The fabricated immunosensor was based on gold substrates. The anti-TNF-α antibody (Ab-TNF-α) was electro-addressed onto the gold working electrodes (WEs) through functionalization with 4-carboxymethylaniline (CMA). Cyclic voltammetry (CV) was applied during the functionalization process to characterize the gold WEs surface properties. Finally, the chronoamperometry technique was applied to characterize the modified gold WEs. The use of a secondary antibody anti-TNF-α (Ab-TNF-α-HRP) labelled with horseradish peroxidase (HRP) was investigated using tetramethylbenzidine (TMB) as electrochemical substrate. A sandwich-type detection strategy was then employed for TNF-α detection through the labelled antibody Ab-TNF-α-HRP activity in a TMB solution. Under the optimal experimental conditions, the specificity of the immunosensor was investigated by analysing solutions containing possible salivary interferences represented by other molecules secreted in acute stage of inflammation such as interleukin-10 (IL-10) and the hormone cortisol. The developed immunosensor showed good performances for Ag-TNF-α cytokine detection within the range of 1 pg mL−1–30 pg mL−1 with a limit of detection (LOD) of 1 pg mL−1. As there is a correlation between TNF-α and the severity of heart failure (HF), this new immunosensor may represent a promising bioanalytical tool for the HF monitoring by saliva analysis. Moreover, the CA technique provides analyses in 5 s for each concentration, which save time and provides rapid data to doctors and clinicians.

A reliable method for the determination of carbonyl compounds in exhaled breath based on on-sorbent derivatization coupled with thermal desorption and gas chromatography-tandem mass spectrometry is described. The analytical performances were optimized for a mixture of C2-C9 aldehydes and C3-C9 ketones, particularly interesting for clinical applications, by using an internal standard and applying a 2(3) full factorial design. A volume of sample (250 ml) was loaded at 50 ml min(-1) into a Tenax GR sorbent tube containing 130 nmol of O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. All compounds showed a limit of detection lower than 200 pptv. The yield of the derivatization procedure was normalized by adding to the sample a known amount of D-6-acetone as an internal standard. This allowed halving the relative standard deviation to 10% and 15% for the mono-and di-carbonyl compounds, respectively, thus improving reliability. The optimized method was applied to the determination of carbonyl compounds in 12 breath samples collected from four patients suffering from heart failure during hospitalization.

The study was aimed to investigate the response in psoriatic patients of the two primary neuroendocrine systems, namely the Autonomic Nervous System and the Hypothalamic-Pituitary-Adrenal (HPA) axis, whose main biomarkers of activation are salivary α-amylase and cortisol, respectively. Reliable analytical procedures for the determination of salivary α-amylase enzymatic activity and cortisol concentration in oral fluid were developed. The non-invasive sampling that does not require trained personnel represents one of the main advantages of oral fluid analysis compared to the analysis of blood and its derivatives (e.g. plasma). Since oral fluid offers the advantage of a simple and stress free sample collection, it is particularly useful to quantify stress related molecules. α-amylase activity was measured by a spectrometric method, whereas salivary cortisol by Reversed-Phase High-Performance Liquid Chromatography coupled to Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry. The effect of salivary pH and flow rate on salivary α-amylase activity and cortisol were also investigated. Finally, both methods were preliminary tested on oral fluid samples of psoriatic volunteers underwent to a psychosocial stress task (the Trier Social Stress Test), as a first step of a more comprehensive study on the responsiveness of psoriatic subjects to stressors.

pH measuring and monitoring is fundamental to understand or control many chemical processes in biological, industrial or environmental fields. Potentiometric measurements by a glass electrode is the most common method to measure pH, although single-use paper strips are also widely used. Other methods include the use of hydrogen, quinhydron, and antimony electrodes, the imaging using pH-sensitive indicators such as dyes or proteins, and the use of ion-selective field effect transistor (ISFET). Due to the chemical reactivity of both sides of its 2D structure, nanometer thickness, high electron mobility, high reactivity to oxygen groups such as OH − , and ultrafast optical response, graphene has the potential to be used for the fabrication of nanoscale, wide-range, high-sensitivity and flexible pH sensors. This review describes how graphene, graphene oxide and reduced graphene oxide can be used to fabricate pH-sensitive devices (e.g. solution-gated FETs, solid-gate FETs, electrochemical sensors, and pH-sensitive quantum dots). The various configurations are reported along with the advantages and current limitations.

This study was aimed at evaluating the influence of sampling procedure on the determination of uric acid and lactate in oral fluid. Samples of non-stimulated and stimulated oral fluid were collected from 22 healthy volunteers. Different frequencies of stimulation were obtained by moving a polyester swab within the mouth at 50, 100 and 150 min − 1 . Three oral fluid samples were consecutively collected from a subgroup of 5 volunteers at a constant stimulation (70 min − 1 ) and at a self-selected pace to evaluate reproducibility. The urate concentration in oral fluid decreased with the increase of the stimulation and oral fluid flow rate (r = − 0.98, p = 0.01). Also, the lactate concentration was much (p = 0.03, two tailed) lower in samples collected under a mild stimulation (50 min − 1 ) than in samples collected without stimulation. Nevertheless, it progressively increased at higher stimulations (100 and 150 min − 1 ). A transfer process mediated by membrane carriers (i.e. urate transporter and organic anion transporters) was hypothesized to explain these results. Finally, a reduced variability (relative standard deviation below 10%) of the urate concentration was obtained when oral fluid was sampled at constant stimulation (70 min − 1 ), but it increased remarkably (20–50%) in case of sampling at self-selected pace. Nevertheless, expressing the salivary excretion of urate as a function of time (μg min − 1 ), the variability of sampling procedure at self-selected pace was lower than 15%.

International audience; The aim of this work is to present a computational approach for the estimation of the severity of heart failure (HF) in terms of New York Heart Association (NYHA) class and the characterization of the status of the HF patients, during hospitalization, as acute, progressive or stable. The proposed method employs feature selection and classification techniques. However, it is differentiated from the methods reported in the literature since it exploits information that biomarkers fetch. The method is evaluated on a dataset of 29 patients, through a 10-fold-cross-validation approach. The accuracy is 94 and 77% for the estimation of HF severity and the status of HF patients during hospitalization, respectively.

This work presents a reliable analytical procedure combining micro-extraction by packed sorbent (MEPS) and ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry to determine 8-iso prostaglandin F2α, 8-iso prostaglandin E2 and prostaglandin E2 in dried blood spots (DBSs). To reach this goal, we optimized a fast semi-automated MEPS procedure for the clean-up and pre-concentration of the analytes extracted from a single DBS (50 μL) by a 70:30 v/v methanol:water mixture. Limits of detection of about 20 pg mL−1, satisfactory recoveries (90–110%) and very good intra- and inter-day precisions (RSD ≤10%) were obtained for all the analytes. The innovative addition of internal standards on the filter paper before DBS sampling allowed to compensate changes in the amount of analyte during storage. Since prostanoids and isoprostanoids are biomarkers involved in the pathogenesis and progression of many diseases (e.g. ductal patency, diabetic nephropathy, and acute lung injury), our analytical method offers interesting diagnostic and prognostic opportunities in the medical field. The present method is currently used for the analysis of such biomarkers in DBSs from preterm newborns collected in the clinical setting.

Hydrogen sulfide (H₂S) is an endogenous gasotransmitter, which mediates important physiological effects in the cardiovascular system. Accordingly, an impaired production of endogenous H₂S contributes to the pathogenesis of important cardiovascular disorders, such as hypertension. Therefore, exogenous compounds, acting as H₂S-releasing agents, are viewed as promising pharmacotherapeutic agents for cardiovascular diseases. Thus, this paper aimed at evaluating the H₂S-releasing properties of some aryl isothiocyanate derivatives and their vascular effects. The release of H₂S was determined by amperometry, spectrophotometry and gas/mass chromatography. Moreover, the vascular activity of selected isothiocyanates were tested in rat conductance (aorta) and coronary arteries. Since H₂S has been recently reported to act as an activator of vascular Kv7 potassium channels, the possible membrane hyperpolarizing effects of isothiocyanates were tested on human vascular smooth muscle (VSM) cells by spectrofluorescent dyes. Among the tested compounds, phenyl isothiocyanate (PhNCS) and 4-carboxyphenyl isothiocyanate (PhNCS-COOH) exhibited slow-H₂S-release, triggered by organic thiols such as L-cysteine. These compounds were endowed with vasorelaxing effects on conductance and coronary arteries. Moreover, these two isothiocyanates caused membrane hyperpolarization of VSM cells. The vascular effects of isothiocyanates were strongly abolished by the selective Kv7-blocker XE991. In conclusion, the isothiocyanate function can be viewed as a suitable slow H₂S-releasing moiety, endowed with vasorelaxing and hypotensive effects, typical of this gasotransmitter. Thus, such a chemical moiety can be employed for the development of novel chemical tools for basic studies and promising cardiovascular drugs.

The aim of this work is to present a machine learning based method for the prediction of adverse events (mortality and relapses) in patients with heart failure (HF) by exploiting, for the first time, measurements of breath and saliva biomarkers (Tumor Necrosis Factor Alpha, Cortisol and Acetone). Data from 27 patients are used in the study and the prediction of adverse events is achieved with high accuracy (77%) using the Rotation Forest algorithm. As in the near future, biomarkers can be measured at home, together with other physiological data, the accurate prediction of adverse events on the basis of home based measurements can revolutionize HF management.

A method for the simultaneous determination of warfarin and its active metabolites (warfarin alcohols) in dried blood spots samples was developed and validated. The procedure consisted of the collection of blood sample spots on Whatman 903 filter paper and the liquid extraction of the analytes by a 3:1 v/v methanol/acetonitrile mixture from 6 mm diameter disks punched out from dried blood spots. Extracted samples were analyzed by ultra-high performance liquid chromatography coupled to electrospray positive ionization and tandem mass spectrometry. Chromatographic separation was carried out in isocratic condition at 25 °C on a Poroshell 120 EC-C18 reversed phase column with a mobile phase consisting of 65% water containing 0.1% (v/v) formic acid and 35% acetonitrile containing 0.1% (v/v) formic acid at a flow rate of 0.5 mL min − 1 . The method did not show any detectable interference or matrix effect. The limits of detection were 0.007, 0.006 and 0.004 ng/mL for RR/SS-warfarin alcohols, RS/SR-warfarin alcohols and warfarin, respectively. Warfarin and warfarin alcohols recovery from dried blood spots sample was almost quantitative (range 96–103%). The intra- and inter-day precision (expressed as relative standard deviation) was always below 10%. Time stability studies highlighted that the concentrations of warfarin and both diastereoisomers of warfarin alcohols in a pooled blood sample were stable for at least 1 month at − 20 °C and after 4 cycles of thaw–freeze. Moreover, warfarin, RR/SS- and RS/SR-warfarin alcohols concentrations in the dried blood spots were stable for at least 7 days at 25 °C. Hematocrit value had a minor influence on the analytical result compared to blood drop volume. The method was successfully applied to the analysis of 15 blood samples from patients undergoing warfarin therapy and demonstrated its suitability as an alternative for warfarin and warfarin alcohols measurement in plasma. Good correlations between concentrations in plasma and dried blood spots were demonstrated for all three analytes, with correlation coefficients r ≥ 0.95. Warfarin concentration in dried blood spot correlated well with warfarin dosage (r = 0.70, p These preliminary results highlighted that the developed method can provide useful information for the therapeutic drug monitoring of warfarin and its active metabolites, although further studies in a larger clinical trial are needed.

In the last decades, the possibility to assess physiological states, monitor disease onset and progression, as well as monitor post-treatment therapeutic outcomes through a non-invasive approach became one of the most desirable goals for healthcare research. In this respect, saliva analysis can represent a very interesting biological matrix which has high potential for the surveillance of general health and disease. Potentially important biomarkers are increased in saliva during local and systemic inflammation. In the present study, we have developed a highly sensitive biosensor for TNF-α detection in human saliva. Therefore, a fully integrated electrochemical biosensor platform was developed in order to increase the sensitivity of detection, decrease the time of analysis, and to simultaneously detect varying cytokine biomarkers using eight gold working microelectrodes (WE). The monoclonal antibodies (mAb) anti-human Tumor Necrosis Factor-alpha (anti-TNF-α) were immobilized onto gold WE through functionalization with carboxyl diazonium. Cyclic voltammetry (CV) was applied during the microelectrode functionalization process to characterize the gold microelectrode surface properties. Finally, electrochemical impedance spectroscopy (EIS) combined with standard added method was used to characterize the modified gold microelectrodes as well as for the detection of TNF-α both in standard solution and in artificial saliva. The high selectivity of the biosensor platform was demonstrated by analysing solution containing other cytokines may representing possible interferences. TNF-α cytokines were analysed in PBS buffer, artificial saliva and real human saliva within the range 1–100 pg/mL which is the critical range for patients suffering from heart failure. The first preliminary results of EIS analyses in human saliva gave a result of 3.1 pg/mL which is very promising for rapid analysis for cytokines detection.

International audience; The aim of this work is to estimate the medication adherence of patients with heart failure through the application of a data mining approach on a dataset including information from saliva and breath biomarkers. The method consists of two stages. In the first stage, a model for the estimation of adherence risk of a patient, exploiting anamnestic and instrumental data, is applied. In the second stage, the output of the model, accompanied with data from saliva and breath biomarkers, is given as input to a classification model for determining if the patient is adherent, in terms of medication. The method is evaluated on a dataset of 29 patients and the achieved accuracy is 96%.

This work presents a computerized system to monitor mouth pressure, tidal volume, exhaled airflow, respiration rate and end-tidal partial pressure of CO 2 during breath collection. The system was used to investigate the effect of different respiratory rates on the volatile organic compounds (VOCs) concentrations in exhaled breath. For this purpose, VOCs with well-defined biochemical pathways and different chemical and physical properties were selected as biomarkers related to metabolism (acetone and isopropyl alcohol), cholesterol synthesis (isoprene) and intestinal microflora activity (ethanol). Mixed breath was collected from a nominally healthy volunteer in resting conditions by filling a Nalophan bag. The subject followed a regimented breathing pattern at different respiratory rates (10, 30 and 50 breaths per minute). Results highlight that ventilation pattern strongly influences the concentration of the selected compounds. The proposed system allows exhaled breath to be collected also in patients showing dyspnea such as in case of chronic heart failure, asthma and pulmonary diseases.

Nalophan, Tedlar and Cali-5-Bond polymeric bags were compared to determine the most suitable type for breath sampling and storage when volatile organic compounds are to be determined. Analyses were performed by thermal desorption gas chromatography mass spectrometry. For each bag, the release of contaminants and the chemical stability of a gaseous standard mixture containing eighteen organic compounds, as well as the CO2 partial pressure were assessed. The selected compounds were representative of breath constituents and belonged to different chemical classes (i.e. hydrocarbons, ketones, aldehydes, aromatics, sulfurs and esters). In the case of Nalophan, the influence of the surface-to-volume ratio, related to the bag's filling degree, on the chemical stability was also evaluated. Nalophan bags were found to be the most suitable in terms of contaminants released during storage (only 2-methyl-1,3-dioxalane), good sample stability (up to 24 h for both dry and humid samples), and very limited costs (about 1 € for a 20 liter bag). The (film) surface-to-(sample) volume ratio was found to be an important factor affecting the stability of selected compounds, and therefore we recommended to fill the bag completely.

This work presents a breath sampler prototype automatically collecting end-tidal (single and multiple breaths) or dead space air fractions (multiple breaths). This result is achieved by real time measurements of the CO2 partial pressure and airflow during the expiratory and inspiratory phases. Suitable algorithms, used to control a solenoid valve, guarantee that a Nalophan (R) bag is filled with the selected breath fraction even if the subject under test hyperventilates. The breath sampler has low pressure drop (

The analytical performances of needle trap micro-extraction (NTME) coupled with gas chromatography-tandem mass spectrometry were evaluated by analyzing a mixture of twenty-two representative breath volatile organic compounds (VOCs) belonging to different chemical classes (i.e. hydrocarbons, ketones, aldehydes, aromatics and sulfurs). NTME is an emerging technique that guarantees detection limits in the pptv range by pre-concentrating low volumes of sample, and it is particularly suitable for breath analysis. For most VOCs, detection limits between 20 and 500 pptv were obtained by pre-concentrating 25 ml of a humidified standard gas mixture at a flow rate of 15 ml min-1. For all compounds, inter- and intra-day precisions were always below 15%, confirming the reliability of the method. The procedure was successfully applied to the analysis of exhaled breath samples collected from forty heart failure (HF) patients during their stay in the University Hospital of Pisa. The majority of patients (about 80%) showed a significant decrease of breath acetone levels (a factor of 3 or higher) at discharge compared to admission (acute phase) in correspondence to the improved clinical conditions during hospitalization, thus making this compound eligible as a biomarker of HF exacerbation.

a b s t r a c t Volatile anaesthetics and disinfection chemicals pose ubiquitous inhalation and dermal exposure risks in hospital and clinic environments. This work demonstrates specific non-invasive breath biomonitoring methodology for assessing staff exposures to sevoflurane (SEV) anaesthetic, documenting its metabolite hexafluoroisopropanol (HFIP) and measuring exposures to isopropanol (IPA) dermal disinfection fluid. Methods are based on breath sample collection in Nalophan bags, followed by an aliquot transfer to adsorption tube, and subsequent analysis by thermal desorption gas chromatography-mass spectrometry (TD-GC-MS). Ambient levels of IPA were also monitored. These methods could be generalized to other common volatile chemicals found in medical environments. Calibration curves were linear (r2 = 0.999) in the investigated ranges: 0.01-1000 ppbv for SEV, 0.02-1700 ppbv for IPA, and 0.001-0.1 ppbv for HFIP. The instrumental detection limit was 10 pptv for IPA and 5 pptv for SEV, both estimated by extracted ion-TIC chromatograms, whereas the HFIP minimum detectable concentration was 0.5 pptv as estimated in SIM acquisition mode. The methods were applied to hospital staff working in operating rooms and clinics for blood draws. SEV and HFIP were present in all subjects at concentrations in the range of 0.7-18, and 0.002-0.024 ppbv for SEV and HFIP respectively. Correlation between IPA ambient air and breath concentration confirmed the inhalation pathway of exposure (r = 0.95, p < 0.001) and breath-borne IPA was measured as high as 1500 ppbv. The methodology is easy to implement and valuable for screening exposures to common hospital chemicals. Although the overall exposures documented were generally below levels of health concern in this limited study, outliers were observed that indicate potential for acute exposures. © 2015 Published by Elsevier B.V.