Sensitive Detection Of Nitric Oxide Research Articles

Development of an innovative turn-on fluorescent probe for targeted in-vivo detection of nitric oxide in rat brain extracts as a biomarker for migraine disease

Nitric oxide (NO) is one of the reactive nitrogen species (RNS) that has been proposed to be a key signaling molecule in migraine. Migraine is a neurological disorder that is linked to irregular NO levels, which necessitates precise NO quantification for effective diagnosis and treatment. This work introduces a novel fluorescent probe, 2,3-diaminonaphthelene-1,4-dione (DAND), which was designed and synthesized to selectively detect NO in-vitro and in-vivo as a migraine biomarker. DAND boasts high aqueous solubility, biocompatibility, and facile synthesis, which enable highly selective and sensitive detection of NO under physiological conditions. NO reacts with diamine moieties (recognition sites) of DAND, results in the formation of a highly fluorescent product (DAND-NO) known as 1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione at λem 450 nm. The fluorescence turn-on sensing mechanism operates through an intramolecular charge transfer (ICT) mechanism. To maximize fluorescence signal intensity, parameters including DAND concentration, reaction temperature, reaction time and pH were systematically optimized for sensitive and precise NO determination. The enhanced detection capability (LOD = 0.08 μmol L−1) and high selectivity of the probe make it a promising tool for NO detection in brain tissue homogenates. This demonstrates the potential diagnostic value of the probe for individuals suffering from migraine. Furthermore, this study sheds light on the potential role of zolmitriptan (ZOLM), an antimigraine medication, in modulating NO levels in the brain of rats with nitroglycerin-induced migraine, emphasizing its significant impact on reducing NO levels. The obtained results could have significant implications for understanding how ZOLM affects NO levels and may aid in the development of more targeted and effective migraine treatment strategies.

Sensitive electrochemical measurement of nitric oxide released from living cells based on dealloyed PtBi alloy nanoparticles.

Nitric oxide (NO), as a vital signaling molecule related to different physiological and pathological processes in living systems, is closely associated with cancer and cardiovascular disease. However, the detection of NO in real-time remains a difficulty. Here, PtBi alloy nanoparticles (NPs) were synthesized, dealloyed, and then fabricated to NP-based electrodes for the electrochemical detection of NO. Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and nitrogen physical adsorption/desorption show that dealloyed PtBi alloy nanoparticles (dPtBi NPs) have a porous nanostructure. Electrochemical impedance spectroscopy and cyclic voltammetry results exhibit that the dPtBi NP electrode possesses unique electrocatalytic features such as low charge transfer resistance and large electrochemically active surface area, which lead to its excellent NO electrochemical sensing performance. Owing to the higher density of catalytical active sites formed PtBi bimetallic interface, the dPtBi NP electrode displays superior electrocatalytic activity toward the oxidation of NO with a peak potential at 0.74V vs. SCE. The dPtBi NP electrode shows a wide dynamic range (0.09-31.5μM) and a low detection limit of 1nM (3σ/k) as well as high sensitivity (130 and 36.5 μA μM-1cm-2). Moreover, the developed dPtBi NP-based electrochemical sensor also exhibited good reproducibility (RSD 5.7%) and repeatability (RSD 3.4%). The electrochemical sensor was successfully used for the sensitive detection of NO produced by live cells. This study indicates a highly effective approach for regulating the composition and nanostructures of metal alloy nanomaterials, which might provide new technical insights for developing high-performance NO-sensitive systems, and have important implications in enabling real-time detection of NO produced by live cells.

Bio-Inspired Electrochemical Detection of Nitric Oxide Promoted by Coordinating the Histamine-Iron Phthalocyanine Catalytic Center on Microelectrode.

Biomimetic structures to fabricate bioelectronic interfaces that allow sensors to electrically communicate with electrodes have potential applications in the development of biosensors. Herein, inspired by the structure feature of nitric oxide (NO) sensory protein, we constructed a biomimetically catalytic center, the histamine coordinated iron phthalocyanine (FePc), for efficient and sensitive detection of NO. In specific, NO is recognized by axial tethered FePc, and the oxidative signal of NO on FePc is converted into output signal through electrocatalytic oxidation. Based on the fabricated catalytic structure on the carbon fiber electrode, on one hand, the macrocyclic π system of FePc enabled a rapid redox process, which facilitates electron transfer, thereby greatly improving sensitivity. On the other hand, by coordination with histamine on the electrode surface, FePc can enhance the electrochemical oxidation activity toward NO and promote catalytic detection, which have been revealed by electrochemical characterizations and density functional theory theoretical calculations. The designed electrochemical microsensor exhibits a low limit of detection (0.03 nM) and shows a wide detection range (0.1 nM-2 μM). In addition, the electrochemical microsensor has been successfully used for real-time monitoring of NO release by live cells. So, this work shows a new strategy for the design of bio-inspired electrochemical microsensors that may provide a potential analytical tool for tracing biological signal molecules with enzyme-free biomimetically catalytic centers.

A cellular NO sensor based on aggregation-induced electrochemiluminescence and photoelectron transfer of a novel ruthenium(II) complex

Here, we present a dual amplification strategy of electrochemiluminescence (ECL) based on aggregation-induced and photoelectron transfer (PET) inhibition using a designed ruthenium-based complex for the highly sensitive detection of nitric oxide (NO). A novel ruthenium(II) complex ([Ru(phen)2(DA-phen)]2+, DA-phen: 5,6-diamino-1,10-phenanthroline) was synthesized that uses the O-diaminophenyl group for specific recognition of NO and the ruthenium metal center with 1,10-phenanthroline as the luminophore. In the first step, the 1,10-phenanthroline groups function as the aggregation part. Increasing the volume fraction of a poor solution (H2O: fw, v%) in the DMSO mixture system from 0% to 80% yielded an increase in the fluorescence (FL) and electrochemiluminescence (ECL) intensities by 3- and 42-fold when compared with the FL and ECL intensities in pure DMSO, respectively. The second step involves a PET process. Reacting the complex with NO in physiological pH aqueous media under aerobic conditions to afford its triazole derivative, [Ru(phen)2(TA-phen)]2+ (TA-phen: 5,6-triazole-1,10-phenanthroline), inhibited the electron transfer process, yielding a remarkable further increase in the FL and ECL efficiencies of the Ru(II) complex. The ECL intensities was 86-fold higher in the presence of NO. This dual amplification strategy enabled the sensitive detection of NO from 1.8 × 10–10 to 1.8 × 10–5 M with a detection limit of 60 pM (S/N = 3) and offered excellent specificity with no detectable interference by RNS and metal ions. Furthermore, selective NO detection in cells was achieved using this complex. Thus, this assay should be suitable for applications in environmental toxicology research and early clinical diagnosis.

Gold Nanoclusters Dispersed on Gold Dendrite-Based Carbon Fibre Microelectrodes for the Sensitive Detection of Nitric Oxide in Human Serum

Herein, gold nanoclusters (Au NC) dispersed on gold dendrite (Au DS)-based flexible carbon fibre (AuNC@AuDS|CF) microelectrodes are developed using a one-step electrochemical approach. The as-fabricated AuNC@AuDS|CF microelectrodes work as the prospective electrode materials for the sensitive detection of nitric oxide (NO) in a 0.1 M phosphate buffer (PB) solution. Carbon microfibre acts as an efficient matrix for the direct growth of AuNC@AuDS without any binder/extra reductant. The AuNC@AuDS|CF microelectrodes exhibit outstanding electrocatalytic activity towards NO oxidation, which is ascribed to their large electrochemical active surface area (ECSA), high electrical conductivity, and high dispersion of Au nanoclusters. As a result, the AuNC@AuDS|CF microelectrodes attain a rapid response time (3 s), a low limit of detection (LOD) (0.11 nM), high sensitivity (66.32 µA µM cm-2), a wide linear range (2 nM-7.7 µM), long-term stability, good reproducibility, and a strong anti-interference capability. Moreover, the present microsensor successfully tested for the discriminating detection of NO in real human serum samples, revealing its potential practicability.

Real-Time In Vivo Sensing of Nitric Oxide Using Photonic Microring Resonators.

Real-time in vivo detection of biomarkers, particularly nitric oxide (NO), is of utmost importance for critical healthcare monitoring, therapeutic dosing, and fundamental understanding of NO's role in regulating many physiological processes. However, detection of NO in a biological medium is challenging due to its short lifetime and low concentration. Here, we demonstrate for the first time that photonic microring resonators (MRRs) can provide real-time, direct, and in vivo detection of NO in a mouse wound model. The MRR encodes the NO concentration information into its transfer function in the form of a resonance wavelength shift. We show that these functionalized MRRs, fabricated using complementary metal oxide semiconductor (CMOS) compatible processes, can achieve sensitive detection of NO (sub-μM) with excellent specificity and no apparent performance degradation for more than 24 h of operation in biological medium. With alternative functionalizations, this compact lab-on-chip optical sensing platform could support real-time in vivo detection of myriad of biochemical species.

CuO/Cu-MOF nanocomposite for highly sensitive detection of nitric oxide released from living cells using an electrochemical microfluidic device.

The integration of large surface area and high catalytic profiles of Cu-MOF and CuO nanoparticles isdescribed toward electrochemical sensing of nitric oxide (NO) in a microfluidic platform. The CuO/Cu-MOF nanocomposite was prepared through hydrothermal method, and its formation was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). The CuO/Cu-MOF nanostructured modified Au electrodes enabled electrocatalytic NO oxidation at 0.6V vs. reference electrode, demonstrating linear response over a broad concentration range of 0.03-1μM and 1-500μM with adetection limit of 7.8nM. The interference effect of organic molecules and common ions was negligible, and the sensing system demonstrated excellent stability. Finally, an electrochemical microfluidic NO sensor was developed to detect of NO released from cancer cells, which were stimulated by L-arginine. Furthermore, in the presence of Fe3+, the stressed cells produced more NO. This work offers considerable potential for its practical applications in clinical diagnostics through determination of chemical symptoms in microliter-volume biological samples. Electrochemical microfluidic NO sensor was developed for detection of NO released from cancer cells. This miniaturized device consumes less materials and provides the basis for greener analytical chemistry.

Rapid Response and High Selectivity for Reactive Nitrogen Species Based on Carbon Quantum Dots Fluorescent Probes

Reactive nitrogen species (RNS) are vital signaling molecules involved in most physiological and pathological processes. Within RNS, nitric oxide (NO) and its metabolite nitrite (NO2−) have been widely applied in medicinal, food, and environmental fields. However, at present, the methods of detecting RNS by fluorescence quenching through chemical reactions have disadvantages, such as long reaction time and weak anti-interference ability. In response to these existing problems, we have developed a novel fluorescent probe, namely, carbon quantum dots (CDs) that are passivated by benzylamine. The obtained CDs (named B-CDs) possess excellent down- and upconversion properties. In particular, upconversion is used to sensitively and selectively measure NO and NO2− under different pH conditions in aqueous media via two different mechanisms (static and dynamic quenching). At pH 7.4, the nanomolar concentration of NO, produced from sodium nitroprusside (SNP) in a concentration-dependent manner, can be rapidly detected with a correlation coefficient (R2) greater than 0.99. Similarly, the quantitative detection of NO2− at pH 1.6 also shows a good linear relationship with a linear range of 0–14 μM, and a limit of detection (LOD) that is as low as 43 nM and 0.65 μM at excitation wavelengths of 800 nm and 375 nm, respectively. Notably, this probe stands out due to its extremely short response time and outstanding selectivity and anti-interference ability against a variety of common interfering substances, while realizing the fast and highly selective and sensitive detection of NO and NO2−. Finally, this probe has been successfully applied to the sensing of NO in fetal bovine serum (FBS) samples and NO2− in milk and tap water samples.

Electrochemically tuning Li1+xFePO4 for high oxidation state of rich Li+ toward highly sensitive detection of nitric oxide

Electrochemical sensors involves electrocatalysis, which greatly relies on the surface electronic state of an electrode but often tedious or complicated surface modification toward a specific reaction. Here a facile electrochemical method is presented for the first time to directly tune Li1+xFePO4 for rich Li+ insertion to an elevated oxidation state for a highly sensitive nitric oxide (NO) sensor, in which the Li+-richest lithium iron phosphate (Li1.66FePO4, 7.3 wt%) over the pristine LiFePO4 (Li+ content of 4.5 wt%) is achieved, delivering a much higher sensitivity (90.38 vs 58.70 μA cm−2 μM−1) and a lower limit of detection (0.12 vs 3.10 nM) than the latter. The enhancement mechanism is investigated, indicating that high Li+ insertion in LiFePO4 rises the surface electronic structure for high oxidation state to strongly adsorb electronegative NO molecules and kinetically prompt the fast electron transfer toward NO oxidation. Additionally, a Li1.66FePO4 modified screen printed electrode was designed and fabricated to directly grow cells as unique sensing platform, by which the cell-released NO could be immediately captured for in situ real-time detection. This direct electrochemical tuning strategy significantly enhances sensing performance to accomplish the highest sensitivity (649.2 μA cm−2 μM−1) among all nonprecious material-based NO sensors while possessing universal significance to design various highly sensitive and selective electrochemical sensors.

Rapid and sensitive detection of nitric oxide by a BODIPY-based fluorescent probe in live cells: glutathione effects.

Nitric oxide (NO) is an important signaling molecule involved in various physiological and pathological processes. The effects of NO depend on its concentration, and the spatial and temporal constraints of the cell microenvironment. Meanwhile, NO can react with some biomolecules such as biothiols, leading to a short biological lifetime. Thus, it is very crucial to establish a real-time visualization method for monitoring NO levels. In this work, we have developed a fluorescent probe, RBA, for NO, with a 3-extended BODIPY as a fluorophore and a secondary amine as the active site. The probe RBA can quickly sense NO (∼10 s) in aerobic solutions to generate a fluorescent N-nitrosamine (RBA-NO, Φf = 0.87) due to blocking of the photoinduced electron transfer (PET) process from the secondary amine to the BODIPY core. This sensing reaction displays high sensitivity (LOD = 10 nM) and high selectivity for NO over relevant analytes except some reducing reagents including biothiols, and a remarkable interference effect is observed ascribed to a competitive reaction with biothiols. Furthermore, the exo- and endogenous detection of NO in live cells and zebra fish was achieved, and it was demonstrated that glutathione (GSH) weakens drastically the fluorescence response by cell-imaging experiments. These results imply that the colorimetric and fluorescence response of the chemosensor for NO depends on the levels of both NO and GSH in environments.

A rapid-response and ratiometric fluorescent probe for nitric oxide: From the mitochondria to the nucleus in live cells

Nitric oxide (NO) is a very important signal molecule implicated in numerous physiological and pathological processes, and its detection is the key to understand these processes. For this reason, various fluorescent probes have been developed for detection analysis of NO. However, few rapid-response (<1 min) and ratiometric fluorescent probe are reported for real-time detection of short-time NO in biological systems. In this work, we report a rapid-response (within several seconds) and ratiometric fluorescent probe, RatioTr, which displays selective and sensitive detection of NO in solutions, and detections of exo- and endogenous NO in live RAW 264.7 cells. Unexpectedly, the probe RatioTr and its sensing product (p-Nus) display different cellular localizations, the mitochondria and the nucleus, which were demonstrated by co-stained experiments. The sensing process of RatioTr toward NO from mitochondria to nucleus was observed in live cells by confocal fluorescence images. Furthermore, the subcellular localizations were demonstrated by measurements of pKa and interaction of p-Nus and DNA. In the presence of a natural DNA, calf thymus DNA, RatioTr is more sensitive to NO (LOD = 2.8 nM). Therefore, due to the nucleus localization together with a high fluorescence efficiency in the nucleus, p-Nus is a good candidate of cell-permeant nucleic acid stain or a fluorescent probe for the nucleus.

New Disposable Nitric Oxide Sensor Fabrication Using GaN Nanowires.

Gallium nitride (GaN) nanowires anchored on the surface of cost-effective pencil graphite electrodes (PGEs) have been developed as a new disposable nitric oxide (NO) sensor through a hydrothermal method followed by annealing treatment. The as-obtained nanomaterials were examined by field emission scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and EIS. Concurrently, the electrocatalytic performance has been analyzed using cyclic voltammetry and amperometric measurements. The experimental results exhibit good electrochemical sensing performance toward the generated NO in NO2– with a wide linear detection range of 1.0 μM to 1.0 mM with a correlation coefficient of 0.999 and a detection limit of 0.180 μM. In addition, the GaN nanowire-modified PGE surface showed high selectivity for the detection of NO as compared to other relevant biomolecules. This confirms that the PGE/GaN nanowire is a new promising electrochemical sensor for the sensitive detection of NO.

(Invited) Design of Nanomaterial-Based Electrochemical Sensor for Sensitive Detection of Nitric Oxide

Nitric oxide (NO) plays important roles in myriad biological processes and is considered as a biomarker of cardiovascular disease, hypertension, symptoms of vaginitis, and cancer. Sensitive detection of NO molecules is vital toward the understanding of cell functionality and pathology as well as to the diagnosis of disease, drug discovery, and biological research [1-4]. Here, we report on the development of high-performance NO electrochemical sensors based on the nanocomposite of reduced graphene oxide (rGO) and AuPt bimetallic nanoparticles (rGO-AuPt) and the nanoporous Au microelectrode. The rGO-AuPt nanocomposites were formed a glassy carbon electrode (GCE) using an electrochemical method. The prepared nanocomposites were tested for the electrochemical detection of NO using differential pulse voltammetry (DPV) and amperometric methods. The dependence of AuPt molar ratios on the electrochemical performance was investigated. Through the combination of the advantages of the high conductivity from rGO and highly electrocatalytic activity from AuPt bimetallic nanoparticles, the rGO-AuPt based NO sensor exhibited a high sensitivity of 7.35 µA µM-1 and a low detection limit of 2.88 nM. Additionally, negligible interference from common ions or organic molecules was observed, and the r-GO-AuPt modified electrode demonstrated excellent stability. Moreover, this optimized electrochemical sensor was practicable for efficiently monitoring the NO released from rat cardiac cells, which were stimulated by L-arginine (L-arg), showing that stressed cells generated over 10 times more NO than normal cells. The nanoporous gold microelectrode was fabricated via an electrochemical alloying/dealloying method. It exhibited a high electrochemically active surface area and excellent performance for the detection of NO with high stability. Based on DPV and amperometric techniques, extremely high sensitivities (21.9 μA μM-1 cm-2 and 14.3 μA μM-1 cm-2) with very low detection limits of 17.0 nM and 1.43 nM, respectively, have been achieved. Moreover, the developed nanoporous Au microelectrode provides a new approach to monitor NO release from different cells, revealing that a significant differential amount of NO can be generated from the normal and stressed rat cardiac cells as well as from the untreated and treated breast cancer cells, promising for the elucidation of cellular stress responses and medical diagnostics.

A sensitive acupuncture needle microsensor for real-time monitoring of nitric oxide in acupoints of rats

This study reports an acupuncture needle modified with an iron-porphyrin functionalized graphene composite (FGPC) for real-time monitoring of nitric oxide (NO) release in acupoints of rats. A gold film was first deposited to the needle surface to enhance the conductivity. The FGPC was prepared via hydrothermal synthesis, and subsequently applied to the tip surface of acupuncture needle by electrochemical deposition method. The functionalized needle enabled a specific and sensitive detection of NO based on the favorably catalytic properties of iron-porphyrin and the excellent conductivity of graphene. Amperometric data showed that the needle achieved not only a low detection limit down to 3.2 nM in PBS solution, but also a satisfactory selectivity. Interestingly, the functionalized needle could be inserted into the acupoints of rats for real-time monitoring of NO in vivo. It was found that a remarkable response to NO was respectively obtained in different acupoints when stimulated by L-arginine (L-Arg), revealing that the release of NO was detectable in acupoints. We expect this work would showcase the applications of acupuncture needle in detecting some important signaling molecules in vivo, and exploring the mechanism of acupuncture treatment.

Sensitive Electrochemical Detection of Nitric Oxide Release from Cardiac and Cancer Cells via a Hierarchical Nanoporous Gold Microelectrode.

The importance of nitric oxide (NO) in many biological processes has garnered increasing research interest in the design and development of efficient technologies for the sensitive detection of NO. Here we report on a novel gold microelectrode with a unique three-dimensional (3D) hierarchical nanoporous structure for the electrochemical sensing of NO, which was fabricated via a facile electrochemical alloying/dealloying method. Following the treatment, the electrochemically active surface area (ECSA) of the gold microelectrode was significantly increased by 22.9 times. The hierarchical nanoporous gold (HNG) microelectrode exhibited excellent performance for the detection of NO with high stability. On the basis of differential pulse voltammetry (DPV) and amperometric techniques, the obtained sensitivities were 21.8 and 14.4 μA μM-1 cm-2, with detection limits of 18.1 ± 1.22 and 1.38 ± 0.139 nM, respectively. The optimized HNG microelectrode was further utilized to monitor the release of NO from different cells, realizing a significant differential amount of NO generated from the normal and stressed rat cardiac cells as well as from the untreated and treated breast cancer cells. The HNG microelectrode developed in the present study may provide an effective platform in monitoring NO in biological processes and would have a great potential in the medical diagnostics.

Selective and sensitive visualization of endogenous nitric oxide in living cells and animals by a Si-rhodamine deoxylactam-based near-infrared fluorescent probe.

Nitric oxide (NO) is a fundamental signaling molecule that regulates virtually every critical cellular function, and it is also a potent mediator of cellular damage in a wide range of conditions mainly via its secondary metabolite peroxynitrite (ONOO-). In this work, we present an o-phenylenediamine (OPD)-locked Si-rhodamine deoxylactam, i.e.deOxy-DALSiR, as a near-infrared fluorescent probe for the selective and sensitive detection of NO in living cells and bodies. Not only could the probe overcome the limitations suffered by widely used and commercialized OPD-type fluorescent NO probes, such as the possible interferences by dehydroascorbic acid/ascorbic acid/methylglyoxal (DHA/AA/MGO), pH-sensitive fluorescence output, and short excitation and emission wavelengths, but it can also avoid serious interference from cysteine (Cys) found in the rhodamine lactam-based fluorescent NO probes developed later. What's more, the probe is fairly sensitive for NO, as evidenced by its rapid fluorescence response rate (within seconds), huge fluorescence off-on ratio (6300-fold), and ultra-low detection limit (0.12 nM). Its effectiveness and practicability have been demonstrated by the successful imaging of endogenous NO in RAW 264.7 macrophages, pancreatic β-cells, and endothelial EA.hy926 cells, as well as in inflamed and diabetic mouse models.

Design and Electrochemical Study of Platinum-Based Nanomaterials for Sensitive Detection of Nitric Oxide in Biomedical Applications.

The extensive physiological and regulatory roles of nitric oxide (NO) have spurred the development of NO sensors, which are of critical importance in neuroscience and various medical applications. The development of electrochemical NO sensors is of significant importance, and has garnered a tremendous amount of attention due to their high sensitivity and selectivity, rapid response, low cost, miniaturization, and the possibility of real-time monitoring. Nanostructured platinum (Pt)-based materials have attracted considerable interest regarding their use in the design of electrochemical sensors for the detection of NO, due to their unique properties and the potential for new and innovative applications. This review focuses primarily on advances and insights into the utilization of nanostructured Pt-based electrode materials, such as nanoporous Pt, Pt and PtAu nanoparticles, PtAu nanoparticle/reduced graphene oxide (rGO), and PtW nanoparticle/rGO-ionic liquid (IL) nanocomposites, for the detection of NO. The design, fabrication, characterization, and integration of electrochemical NO sensing performance, selectivity, and durability are addressed. The attractive electrochemical properties of Pt-based nanomaterials have great potential for increasing the competitiveness of these new sensors and open up new opportunities in the creation of novel NO-sensing technologies for biological and medical applications.

Highly Water-Soluble BODIPY-Based Fluorescent Probe for Sensitive and Selective Detection of Nitric Oxide in Living Cells

A highly water-soluble BODIPY dye bearing electron-rich o-diaminophenyl groups at 2,6-positions was prepared as a highly sensitive and selective fluorescent probe for detection of nitric oxide (NO) in living cells. The fluorescent probe displays an extremely weak fluorescence with fluorescence quantum yield of 0.001 in 10 mM phosphate buffer (pH 7.0) in the absence of NO as two electron-rich o-diaminophenyl groups at 2,6-positions significantly quench the fluorescence of the BODIPY dye via photoinduced electron transfer mechanism. The presence of NO in cells enhances the dye fluorescence dramatically. The fluorescent probe demonstrates excellent water solubility, membrane permeability, and compatibility with living cells for sensitive detection of NO.

Modified Carbon Fiber Microelectodes with Ruthenium Oxide Nanoparticles for Sensitive Detection of Nitric Oxide in Biological Samples

not Available.

High sensitive detection of nitric oxide using laser induced photoacoustic spectroscopy at 213 nm

Trace level detection of nitric oxide (NO) is of great interest for a wide range of applications such as environment and human health. For this purpose, a high sensitive sensor based photoacoustic spectroscopy (PAS) principle has been developed at our laboratory for detection of NO at very low concentration (ppbV). For optimization of the PAS signal and to achieve higher sensitivity, parametric dependence investigation was carried out where PAS signal dependence on NO gas pressure, cell geometry, buffer gas (Ar, N2, He), and laser pulse energy used three PAS cells developed locally. The best sensitivity achieved with three cells was 41, 11, 20 ppbv, respectively. It is worth reporting that the best PAS signal to noise ratio was achieved by using a cylindrical cell having three acoustic filters and argon as a buffer gas.