Chemiluminescent Measurement of Hydrogen Peroxide in the Exhaled Breath Condensate of Healthy and Asthmatic Adults

Sensor platform for noninvasive evaluation of pulmonary oxidative status

We report on sensor platform including both the advanced nanostructured Prussian Blue based hydrogen peroxide sensor and the cooling-free breath aerosol (BA) condenser. The latter provides an order of magnitude more concentrated BA samples as compared to breath condensate collected traditionally through cooling; the conclusion is based on both: specimen's conductivity, the generally accepted dilution marker, and the evaluated H2O2 levels (2.2-3.2 μM for healthy subjects). Reliable detection of submicromolar H2O2 content is possible with the sensor based on nanostructured Prussian Blue (0.45-0.70 nmol cm-2) stabilized with nickel hexacyanoferrate (1.0-1.3 nmol cm-2). A possibility to discover the noninvasively accessed marker for post-COVID-19 syndrome illustrates the horizons of the platform in clinical diagnostics.

Ex Tenebris Lux: Illuminating Reactive Oxygen and Nitrogen Species with Small Molecule Probes

Reactive oxygen and nitrogen species are small reactive molecules derived from elements in the air─oxygen and nitrogen. They are produced in biological systems to mediate fundamental aspects of cellular signaling but must be very tightly balanced to prevent indiscriminate damage to biological molecules. Small molecule probes can transmute the specific nature of each reactive oxygen and nitrogen species into an observable luminescent signal (or even an acoustic wave) to offer sensitive and selective imaging in living cells and whole animals. This review focuses specifically on small molecule probes for superoxide, hydrogen peroxide, hypochlorite, nitric oxide, and peroxynitrite that provide a luminescent or photoacoustic signal. Important background information on general photophysical phenomena, common probe designs, mechanisms, and imaging modalities will be provided, and then, probes for each analyte will be thoroughly evaluated. A discussion of the successes of the field will be presented, followed by recommendations for improvement and a future outlook of emerging trends. Our objectives are to provide an informative, useful, and thorough field guide to small molecule probes for reactive oxygen and nitrogen species as well as important context to compare the ecosystem of chemistries and molecular scaffolds that has manifested within the field.

A novel dual-activatable ultrasensitive chemiluminescent probe for mercury (II) monitoring: From rational design to multiple application

Real-time optical sensing of mercury has been developed rapidly in recent years but remains challenging such as bearing background interference. Herein, a Hg2+ and base dual-activatable ultrasensitive chemiluminescent probe CL-Hg based on benzothiazole-phenoxyl-dioxetane with profits of excitation light-free and minimal interference is presented. The photophysical properties study and sensing performance verified CL-Hg is coupled with unique advantages of long-term detection (more than 400 min), ultrahigh sensitivity (LOD = 0.52 nM), and high specificity to Hg2+, and visualization detection by the paper-based test strips. More importantly, CL-Hg showed the qualitative and quantitative detection capability for Hg2+ with great recyclability in real samples of water, seafood, and beverages, holding great potential for on-site monitoring of Hg2+ levels in the actual samples. To our knowledge, this is the first work achieving the detection of Hg2+ by chemiluminescence. Overall, the Hg2+-activated visualization platform offers a practical method for detecting Hg2+ in various application scenarios.

The Role of Exhaled Breath Condensate in Chronic Inflammatory and Neoplastic Diseases of the Respiratory Tract

Asthma and chronic obstructive pulmonary disease (COPD) are among the most common chronic respiratory diseases. Chronic inflammation of the airways leads to an increased production of inflammatory markers by the effector cells of the respiratory tract and lung tissue. These biomarkers allow the assessment of physiological and pathological processes and responses to therapeutic interventions. Lung cancer, which is characterized by high mortality, is one of the most frequently diagnosed cancers worldwide. Current screening methods and tissue biopsies have limitations that highlight the need for rapid diagnosis, patient differentiation, and effective management and monitoring. One promising non-invasive diagnostic method for respiratory diseases is the assessment of exhaled breath condensate (EBC). EBC contains a mixture of volatile and non-volatile biomarkers such as cytokines, leukotrienes, oxidative stress markers, and molecular biomarkers, providing significant information about inflammatory and neoplastic states in the lungs. This article summarizes the research on the application and development of EBC assessment in diagnosing and monitoring respiratory diseases, focusing on asthma, COPD, and lung cancer. The process of collecting condensate, potential issues, and selected groups of markers for detailed disease assessment in the future are discussed. Further research may contribute to the development of more precise and personalized diagnostic and treatment methods.

Ultrasensitive Online NO Sensor Based on a Distributed Parallel Self-Regulating Neural Network and Ultraviolet Differential Optical Absorption Spectroscopy for Exhaled Breath Diagnosis

The concentration of fractional exhaled nitric oxide (FeNO) is closely related to human respiratory inflammation, and the detection of its concentration plays a key role in aiding diagnosing inflammatory airway diseases. In this paper, we report a gas sensor system based on a distributed parallel self-regulating neural network (DPSRNN) model combined with ultraviolet differential optical absorption spectroscopy for detecting ppb-level FeNO concentrations. The noise signals in the spectrum are eliminated by discrete wavelet transform. The DPSRNN model is then built based on the separated multipeak characteristic absorption structure of the UV absorption spectrum of NO. Furthermore, a distributed parallel network structure is built based on each absorption feature region, which is given self-regulating weights and finally trained by a unified model structure. The final self-regulating weights obtained by the model indicate that each absorption feature region contributes a different weight to the concentration prediction. Compared with the regular convolutional neural network model structure, the proposed model has better performance by considering the effect of separated characteristic absorptions in the spectrum on the concentration and breaking the habit of bringing the spectrum as a whole into the model training in previous related studies. Lab-based results show that the sensor system can stably achieve high-precision detection of NO (2.59-750.66 ppb) with a mean absolute error of 0.17 ppb and a measurement accuracy of 0.84%, which is the best result to date. More interestingly, the proposed sensor system is capable of achieving high-precision online detection of FeNO, as confirmed by the exhaled breath analysis.

Effect of ultrasound-guided stellate ganglion block on lung protection for patients undergoing one-lung ventilation

OBJECTIVE

To explore the potential effect of ultrasound-guided stellate ganglion block (SGB) on lung protection for patients undergoing one-lung ventilation (OLV).

METHODS

A total of 123 patients undergoing elective one-lung ventilation surgery were selected as research subjects in this prospective study. These patients were randomly divided into the SGB group, control group and blank group on average. Stellate ganglion block was carried out in the SGB and control groups. Patients in the SGB group were injected with 6 ml mixture of 0.25% ropivacaine hydrochloride and 1% lidocaine hydrochloride, while those in the control group were injected with 6 mL of 0.9% saline. Punctures weren't performed for patients in the blank group. The same induction and maintenance of general anesthesia was adopted for all three groups. Hemodynamics, respiratory parameters and arterial blood gas analysis were recorded after entering the operation room (T0), pre-OLV (T1), 30 min after OLV (T2), 60 min after OLV (T3), at the end of surgery (T4), and 30 min after extubation (T5). Oxygenation index (OI), pulmonary shunt fraction (Qs/Qt) and pH value were compared at different time points. Intravenous serum was collected at T0, T3 and T5 for the detection of surfactant proteins A (SP-A), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin-6 (IL-6) and interleukin-10 (IL-10) levels, respectively. The complications related to SGB after surgery and the postoperative pulmonary complications within 72 h were recorded.

RESULTS

At T1, T2, and T3, MAP level in SGB group was lower than that in blank and control groups (P<0.05). At T2, and T3, SGB group had lower hear rate (HR), peak airway pressure (Ppeak) and tidal volume (TV) than blank and control groups (all P<0.05). From T2 to T5, SGB group had higher OI but lower Qs/Qt than blank and control groups (both P<0.05). At T3 and T5, SGB group had lower SP-A, IL-6, and MDA levels but higher IL-10 and SOD levels than blank and control groups (all P<0.05). There was one case of hypoxemia in the blank group within 72 h after surgery.

CONCLUSION

Ultrasound-guided SGB has lung-protective effects on patients undergoing OLV, which significantly improves patients' OI, reduces intrapulmonary shunts, declines ventilator-induced lung damage, and inhibits inflammatory response as well as oxidative stress (China Clinical Trial Registry, registration number ChiCTR2000033385, https://www.chictr.org.cn).

Uric acid as a mediator in the correlation between white blood cells and preeclampsia severity: a retrospective cohort study

This study aimed to analyze the independent risk factors for predicting preeclampsia severity and explore its underlying mechanism. Clinical data of patients with preeclampsia were collected from the Medical Information Mart for Intensive Care (MIMIC)-IV database. Univariate and multivariate analyses were employed to assess the significant factors associated with preeclampsia severity. Additionally, we performed multivariate logistic regression analysis and mediation analysis to investigate the potential regulatory path. Based on inclusion and exclusion criteria, 731 participants were enrolled: severe preeclampsia (n = 381) and mild to moderate preeclampsia (n = 350). Age, white blood cells (WBC), platelet, creatinine, albumin, uric acid, aspartate aminotransferase, alanine aminotransferase, international normalized ratio, and prothrombin time were significantly related to preeclampsia severity. Besides, hospital length of stay was significantly higher in the severe group. Notably, age and uric acid were independent predictors for preeclampsia severity. Further, WBC and creatinine were significantly associated with uric acid. Finally, the mediation analysis showed that uric acid was a mediator of the relationship between WBC and preeclampsia severity. In conclusion, WBC might affect preeclampsia severity and progression via the mediation of uric acid. This study might provide novel insight into preventing preeclampsia development.

Biomarkers in exhaled breath condensate as fingerprints of asthma, chronic obstructive pulmonary disease and asthma-chronic obstructive pulmonary disease overlap: a critical review

Asthma, chronic obstructive pulmonary disease (COPD) and asthma-COPD overlap are the third leading cause of mortality around the world. They share some common features, which can lead to misdiagnosis. To properly manage these conditions, reliable markers for early and accurate diagnosis are needed. Over the past 20 years, many molecules have been investigated in the exhaled breath condensate to better understand inflammation pathways and mechanisms related to these disorders. Recently, more advanced techniques, such as sensitive metabolomic and proteomic profiling, have been used to obtain a more comprehensive understanding. This article reviews the use of targeted and untargeted metabolomic methodology to study asthma, COPD and asthma-COPD overlap.

Hypermethylation of RNF125 promotes autophagy-induced oxidative stress in asthma by increasing HMGB1 stability

Asthma is a global chronic airway disease. The expression and role of RNF125, an E3 ubiquitin ligase, in asthma remain uncertain. In this study, we revealed that RNF125 was downregulated in the bronchial epithelium of mice and patients with asthma. Rnf125 hypermethylation was responsible for the low expression of RNF125 in primary airway epithelial cells of mice treated with OVA. Moreover, we demonstrated that RNF125 could attenuate autophagy, oxidative stress, and protect epithelial barrier in vivo and in vitro. Additionally, we identified HMGB1 as a substrate of RNF125, which interacted with the HMG B-box domain of HMGB1 and induced degradation via the ubiquitin proteasome system, reducing autophagy and oxidative stress. Overall, our findings elucidated that hypermethylation of Rnf125 reduced its expression, which promoted autophagy-induced oxidative stress in asthma by increasing HMGB1 stability. These findings offer a theoretical and experimental basis for the pathogenesis of asthma.

The Molecular Basis of Organic Chemiluminescence

Bioluminescence (BL) and chemiluminescence (CL) are interesting and intriguing phenomena that involve the emission of visible light as a consequence of chemical reactions. The mechanistic basis of BL and CL has been investigated in detail since the 1960s, when the synthesis of several models of cyclic peroxides enabled mechanistic studies on the CL transformations, which led to the formulation of general chemiexcitation mechanisms operating in BL and CL. This review describes these general chemiexcitation mechanisms-the unimolecular decomposition of cyclic peroxides and peroxide decomposition catalyzed by electron/charge transfer from an external (intermolecular) or an internal (intramolecular) electron donor-and discusses recent insights from experimental and theoretical investigation. Additionally, some recent representative examples of chemiluminescence assays are given.

An Update on General Chemiexcitation Mechanisms in Cyclic Organic Peroxide Decomposition and the Chemiluminescent Peroxyoxalate Reaction in Aqueous Media

Four-membered ring peroxides are intimately linked to chemiluminescence and bioluminescence transformations, as high-energy intermediates responsible for electronically excited state formation. The synthesis of 1,2-dioxetanes and 1,2-dioxetanones enabled mechanistic studies on their decomposition occurring with the formation of electronically excited carbonyl products in the singlet or triplet state. The third member of this family, 1,2-dioxetanedione, has been postulated as the intermediate in the peroxyoxalate reaction, recently confirmed by kinetic studies on peroxalic acid derivatives. Several general chemiexcitation mechanisms have been proposed as model systems for the chemiexcitation step in efficient bioluminescence and chemiluminescence transformations. In this review article, we discuss the validity and efficiency of the most important chemiexcitation mechanisms, extended to aqueous media, where the efficiency is known to be drastically reduced, specifically in the peroxyoxalate reaction, highly efficient in anhydrous environment, but much less efficient in aqueous media. Mechanistic studies of this reaction will be discussed in diverse aqueous environments, with special attention to the catalysis involved in the thermal reaction leading to the formation of the high-energy intermediate and to the chemiexcitation mechanism, as well as emission quantum yields. Finally, several recent analytical and bioanalytical applications of the peroxyoxalate reaction in aqueous media will be given.

Co3O4 Nanoparticles Uniformly Dispersed in Rational Porous Carbon Nano-Boxes for Significantly Enhanced Electrocatalytic Detection of H2O2 Released from Living Cells

A facile and ingenious method to chemical etching-coordinating a metal-organic framework (MOF) followed by an annealing treatment was proposed to prepare Co₃O₄ nanoparticles uniformly dispersed in rational porous carbon nano-boxes (Co₃O₄@CNBs), which was further used to detect H₂O₂ released from living cells. The Co₃O₄@CNBs H₂O₂ sensor delivers much higher sensitivity than non-etching/coordinating Co₃O₄, offering a limit of detection of 2.32 nM. The wide working range covers 10 nM-359 μM H₂O₂, while possessing good selectivity and excellent reproducibility. Moreover, this biosensor was used to successfully real-time detect H₂O₂ released from living cells, including both healthy and tumor cells. The excellent performance holds great promise for Co₃O₄@CNBs’s applications in electrochemical biomimetic sensing, particularly real-time monitor H₂O₂ released from living cells.

Aggregation-Induced Emission Effect within Peroxyoxalate-Loaded Mesoporous Silica Nanoparticles for Efficient Harvest of Chemiluminescence Energy in Aqueous Solutions

Aggregation-induced emission (AIE) molecules that can avoid the aggregation-caused quenching (ACQ) effect and break the concentration limit have been widely used for biosensing. Similar to fluorescence dyes, AIE molecules can be chemiexcited simply by a peroxyoxalate-based chemiluminescence (CL) reaction, but the hydrolysis of peroxyoxalate is often a problem in an aqueous solution. Herein, we report an AIE effect within peroxyoxalate-loaded silica nanoparticles (PMSNs) for an efficient harvest of CL energy as well as alleviation of bis(2,4,5-trichloro-6-carbopentoxyphenyl) oxalate (CPPO) hydrolysis. Peroxyoxalate (i.e., CPPO) and AIE molecules (i.e., 1,2-benzothiazol-2-triphenylamino acrylonitrile, BTPA) were loaded together within the mesoporous silica nanoparticles (MSNs) to synthesize the BTPA-PMSN nanocomposite. The BTPA-PMSNs not only allowed CPPO to be dispersed well in an aqueous solution but also avoided the hydrolysis of CPPO. Meanwhile, the proximity between BTPA and CPPO molecules in the mesopores of MSNs facilitated the BTPA aggregate to harvest the energy from CL intermediates. Hence, the CL system of BTPA-PMSNs can work efficiently in aqueous solutions at a physiological pH. The CL quantum yield of the BTPA-PMSN system was measured to be 9.91 × 10^-5, about 20 000-fold higher than that obtained in the rhodamine B (RhB, a typical ACQ dye)-PMSN system. Using BTPA-PMSNs for H₂O₂ sensing, a limit of detection (LOD) as low as 5 nM can be achieved, 1000-fold lower than that achieved in the RhB-PMSNs system. Due to the feasibility of working at a physiological pH, this CL system is also quite suitable for the detection of oxidase substrates such as glucose and cholesterol. This BTPA-PMSN CL system with the merits of high CL quantum yield at a physiological pH is appealing for biosensing.

Curly fish scales-like Ni2.5Mo6S6.7 electrodeposited on PEDOT-rGO with uneven surface as ultrafast response electrode for electrocatalytic glucose, nitrite and hydrogen peroxide

The difficulty to achieve rapid detection is the limitation of many enzyme-free sensors today. Thus, designing tri-functionalsensors with ultra-fast and efficientdeterminationis a challenging taskin biological science. Herein, curly fish scales-like Ni_2.5Mo₆S_6.7 active materials was anchored on poly (3,4-ethylenedioxythiophene)-reduced graphene oxide (PEDOT-rGO) hybrid membranes with uneven surface (Ni_2.5Mo₆S_6.7/PEDOT-rGO) as a high-performance tri-functional catalyst for glucose, nitrite and hydrogen peroxide determination.The sensor constructed under optimal conditions exhibited ultrafast response performance towards glucose and nitrite within 2 s, and hydrogen peroxide within 1 s. Meanwhile, it provided the wide linear range with a low detection limit towards glucose (as low as 0.001 mM and up to 15.000 mM, and 0.33 μM), nitrite (as low as 0.001 mM and up to 10.000 mM, and 0.33 µM) and hydrogen peroxide (from 0.010 mM to 7.000 mM, and 0.79 μM), respectively. In addition, the sensor demonstrated satisfied selectivity, repeatability, reproducibility and stability. Furthermore, the sensor has potential application in real samples. This study may provide a new strategy for the construction of tri-functional electrode materials with the ultra-fast response.

Seeking Illumination: The Path to Chemiluminescent 1,2-Dioxetanes for Quantitative Measurements and In Vivo Imaging

Chemiluminescence is a fascinating phenomenon that evolved in nature and has been harnessed by chemists in diverse ways to improve life. This Account tells the story of our research group's efforts to formulate and manifest spiroadamantane 1,2-dioxetanes with triggerable chemiluminescence for imaging and monitoring important reactive analytes in living cells, animals, and human clinical samples. Analytes like reactive sulfur, oxygen and nitrogen species, as well as pH and hypoxia can be indicators of cellular function or dysfunction and are often implicated in the causes and effects of disease. We begin with a foundation in binding-based and activity-based fluorescence imaging that has provided transformative tools for understanding biological systems. The intense light sources required for fluorescence excitation, however, introduce autofluorescence and light scattering that reduces sensitivity and complicates in vivo imaging. Our work and the work of our collaborators were the first to demonstrate that spiroadamantane 1,2-dioxetanes had sufficient brightness and biological compatibility for in vivo imaging of enzyme activity and reactive analytes like hydrogen sulfide (H₂S) inside of living mice. This launched an era of renewed interest in 1,2-dioxetanes that has resulted in a plethora of new chemiluminescence imaging agents developed by groups around the world. Our own research group focused its efforts on reactive sulfur, oxygen, and nitrogen species, pH, and hypoxia, resulting in a large family of bright chemiluminescent 1,2-dioxetanes validated for cell monitoring and in vivo imaging. These chemiluminescent probes feature low background and high sensitivity that have been proven quite useful for studying signaling, for example, the generation of peroxynitrite (ONOO^-) in cellular models of immune function and phagocytosis. This high sensitivity has also enabled real-time quantitative reporting of oxygen-dependent enzyme activity and hypoxia in living cells and tumor xenograft models. We reported some of the first ratiometric chemiluminescent 1,2-dioxetane systems for imaging pH and have introduced a powerful kinetics-based approach for quantification of reactive species like azanone (nitroxyl, HNO) and enzyme activity in living cells. These tools have been applied to untangle complex signaling pathways of peroxynitrite production in radiation therapy and as substrates in a split esterase system to provide an enzyme/substrate pair to rival luciferase/luciferin. Furthermore, we have pushed chemiluminescence toward commercialization and clinical translation by demonstrating the ability to monitor airway hydrogen peroxide in the exhaled breath of asthma patients using transiently produced chemiluminescent 1,2-dioxetanedione intermediates. This body of work shows the powerful possibilities that can emerge when working at the interface of light and chemistry, and we hope that it will inspire future scientists to seek out ever brighter and more illuminating ideas.

Exhaled Breath Condensate-A Non-Invasive Approach for Diagnostic Methods in Asthma

The pathophysiology of asthma has been intensively studied, but its underlying mechanisms such as airway inflammation, control of airway tone, and bronchial reactivity are still not completely explained. There is an urgent need to implement novel, non-invasive diagnostic tools that can help to investigate local airway inflammation and connect the molecular pathways with the broad spectrum of clinical manifestations of asthma. The new biomarkers of different asthma endotypes could be used to confirm diagnosis, predict asthma exacerbations, or evaluate treatment response. In this paper, we briefly describe the characteristics of exhaled breath condensate (EBC) that is considered to be an interesting source of biomarkers of lung disorders. We look at the composition of EBC, some aspects of the collection procedure, the proposed biomarkers for asthma, and its clinical implications. We also indicate the limitations of the method and potential strategies to standardize the procedure of EBC collection and analytical methods.