Real-time Monitoring Of Nitric Oxide Research Articles

Utilization of in-situ self-supporting materials for the preparation of flexible and stretchable electrodes for the detection of nitric oxide released from cells

Real-time monitoring of nitric oxide from endogenously cells released is crucial for revealing their physiological activities or pathological processes. However, designing electrochemical sensors for real-time monitoring at the cellular level is challenging due to the simultaneous requirements of sensitivity, transient recording capability, and biocompatibility. Combining the universally self-supported grown highly active materials with stretchable conductive flexible substrates holds promise for achieving sensitive detection of cells and real-time monitoring of mechanically induced biomolecular release. However, existing manufacturing strategies for highly sensitive stretchable flexible electrochemical sensors still face significant challenges due to low material activity, high processing requirements, and the complexity of further designing membrane electrodes. Here, we designed a method of in-situ self-supported growth to grow Co-doped Ni(OH)2 structures on rigid Ti foil. Leveraging the synergistic effect of Co and Ni, sensitive detection of NO was achieved, enabling real-time monitoring of trace amounts of NO released by Raw 264.7 cells. Based on this material, using catalytic ink method, it was transferred to low-resistance flexible ITO film (LIF), enabling real-time monitoring of mechanically induced NO release from Human Umbilical Vein Endothelial Cells (HUVECs) cells.

Using Metalloporphyrin Nanosensors for In Situ Monitoring and Measurement of Nitric Oxide and Peroxynitrite in a Single Human Neural Progenitor Cell.

Nitric oxide (NO) is an inorganic signaling molecule that plays a crucial role in the regulation of numerous physiological functions. An oxidation product of the cytoprotective NO is cytotoxic peroxynitrite (ONOO-). In biological systems, the concentrations of NO and ONOO- are typically transient, ranging from nanomolar to micromolar, and these increases are normally followed by a swift return to their basal levels due to their short life spans. To understand the vital physiological role of NO and ONOO- in vitro and in vivo, sensitive and selective methods are necessary for direct and continuous NO and ONOO- measurements in real time. Because electrochemical methods can be adjusted for selectivity, sensitivity, and biocompatibility in demanding biological environments, they are suitable for real-time monitoring of NO and ONOO- release. Metalloporphyrin nanosensors, described here, have been designed to measure the concentration of NO and ONOO- produced by a single human neural progenitor cell (hNPC) in real time. These nanosensors (200-300 nm in diameter) can be positioned accurately in the proximity of 4-5 ± 1 μm from an hNPC membrane. The response time of the sensors is better than a millisecond, while detection limits for NO and ONOO- are 1 × 10-9 and 3 × 10-9 mol/L, respectively, with a linear concentration response of up to about 1 μM. The application of these metalloporphyrin nanosensors for the efficient measurement of the concentrations of NO and ONOO- in hNPCs is demonstrated, providing an opportunity to observe in real time the molecular changes of the two signaling molecules in situ.

Golgi-targeted NIR fluorescent probe with large stokes shift for real-time monitoring of nitric oxide in depression model

Depression is a debilitating mental illness that poses a serious threat to human health. Nitric Oxide (NO), as an important gasotransmitter, is closely associated with the pathogenesis of depressive disorders. Effective monitoring of NO fluctuation is beneficial for the diagnosis of depression and therapy assessment of antidepressants. Currently, there is a lack of effective methods for rapidly and sensitively identifying NO and elucidating its relationship with depression diseases. Herein, we developed a NIR dye TJ730-based fluorescent probe TJ730-Golgi-NO incorporating benzenesulfonamide as a Golgi-targeted moiety and the thiosemicarbazide group for NO detection. The probe exhibited turn-on fluorescence ability and a large Stokes shift of 158 nm, which shows high sensitivity, selectivity, and rapid response (<1 min) for NO detection. TJ730-Golgi-NO could detect exogenous and endogenous NO in cells stimulated by Glu and LPS, and target Golgi apparatus. Moreover, we disclose a significant increase of NO in the depression model and a weak fluorescence evidenced in the fluoxetine-treated depression mice. This study provides a competent tool for studying the function of NO and helping improve the effective treatment of depression diseases.

Carbon nanotube-interconnected ruthenium phthalocyanine nanoparticles used for real-time monitoring of nitric oxide released from vascular endothelial barrier model

Real-time monitoring of nitric oxide (NO) is of great importance in diagnosing the physiological functions of neurotransmission, cardiovascular, and immune systems. This study reports the carbon nanotube-interconnected ruthenium phthalocyanine nanoparticle nanocomposite and its applicability in construction of an electrochemical platform, which could real-time detect NO released from the vascular endothelial barrier (VEB) model in cell culture medium. The nanocomposite exhibits regular morphology, uniform particle size, and excellent electro-catalytic activity to electrochemical oxidation of NO. Under optimal conditions, the electrochemical device has high sensitivity (0.871 μA μM−1) and can selectively detect NO down to the concentration of 6 × 10−10 M. The human brain microvascular endothelial cells were cultured onto the Transwell support to construct the VEB model. Upon stimulated by L-arginine, NO produced by the VEB diffuses into the bottom chamber of the Transwell, and is real-time monitored by the electrochemical device. Moreover, evaluation of the NO inhibition by drug is realized using the electrochemical device-Transwell platform. This simple and sensitive platform would be of great interesting for evaluating the endothelial function or its pathological states, and screening the related drugs or chemicals.

Rational Design of Cu-Doped Tetrahedron of Spinel Oxide for High-Performance Nitric Oxide Electrochemical Sensor

The real-time detection of nitric oxide (NO) in living cells is essential to reveal its physiological processes. However, the popular electrochemical detection strategy is limited to the utilization of noble metals. The development of new detection candidates without noble metal species still maintaining excellent catalytic performance has become a big challenge. Herein, we propose a spinel oxide doped with heteroatom-Cu-doped Co3O4 (Cu-Co3O4) for the sensitive and selective detection of NO release from the living cells. The material is strategically designed with Cu occupying the tetrahedral (Td) center of Co3O4 through the formation of a Cu-O bond. The introduced Cu regulates the local coordination environment and optimizes the electronic structure of Co3O4, hybridizing with the N 2p orbital to enhance charge transfer. The CuTd site can well inhibit the current response to nitrite (NO2-), resulting in a high improvement in the electrochemical oxidation of NO. The selectivity of Cu-Co3O4 can be markedly improved by the pore size of the molecular sieve and the negative charge on the surface. The rapid transmission of electrons is due to the fact that Cu-Co3O4 can be uniformly and densely in situ grown on Ti foil. The rationally designed Cu-Co3O4 sensor displays excellent catalytic activity toward NO oxidation with a low limit of detection of 2.0 nM (S/N = 3) and high sensitivity of 1.9 μA nM-1 cm-2 in cell culture medium. The Cu-Co3O4 sensor also shows good biocompatibility to monitor the real-time NO release from living cells (human umbilical vein endothelial cells: HUVECs; macrophage: RAW 264.7 cells). It was found that a remarkable response to NO was obtained in different living cells when stimulated by l-arginine (l-Arg). Moreover, the developed biosensor could be used for real-time monitoring of NO released from macrophages polarized to a M1/M2 phenotype. This cheap and convenient doping strategy shows universality and can be used for sensor design of other Cu-doped transition metal materials. The Cu-Co3O4 sensor presents an excellent example through the design of proper materials to implement unique sensing requirements and sheds light on the promising strategy for electrochemical sensor fabrication.

Rapid real-time monitoring of NO released from living cells using multi-walled carbon nanotube-7,7,8,8-tetracyanoquinonedimethyl-polylysine sensors

Nitric oxide (NO) is an important but short-lived signaling molecule that is released from living cells. Real-time monitoring of NO release is useful for understanding normal cellular physiology and pathology. Herein, a convenient and efficient NO sensor was developed using multiwalled carbon nanotubes (MWCNTs)-7,7,8,8-tetracyanoquinodimethan (TCNQ)-polylysine (PLL) modified screen-printed electrode (SPE). The construction of the sensor (MWCNTs/TCNQ/PLL/SPE) was based on the synergic effect of the good conductivity of TCNQ and the high surface area of MWCNTs. The introduction of the cell-adhesive molecule PLL significantly enhanced the cytocompatibility, resulting in excellent cell attachment and growth. The resulting MWCNTs/TCNQ/PLL/SPE was successfully used for the real-time detection of NO released from living human umbilical vein endothelial cells (HUVECs) cultured on it. The MWCNTs/TCNQ/PLL/SPE was further used to detect NO release from oxidative-injured HUVECs with and without resveratrol to also preliminarily assess the effect of resveratrol against oxidative damage. The sensor developed in this study showed good performance for the real-time detection of NO released by HUVECs under different conditions and has potential applications in the diagnosis of biological processes and the screening of drug treatment effects.

Ionic liquid functionalized metal-organic framework nanowires for sensitive and real-time electrochemical monitoring of nitric oxide released from living cells.

Sensitive, selective, and real-time detection of nitric oxide (NO) is still challenging due to its rapid diffusion, short half-life, and low concentration in living systems. Herein, we synthesized well-defined ultralong metal-organic framework nanowires (MOFNWs) that were further uniformly covered with gold nanoparticle (AuNPs) and ionic liquids (ILs) and applied these NWs to detect and monitor NO released from living cells. In this system, ILs and AuNPs act as excellent catalysts for electrochemical oxidation of NO. By taking advantage of the synergetic effect between ILs, AuNPs and MOFNWs, the composite (IL@Au@MOFNWs) sensor probe displays excellent electrocatalytic activity toward NO oxidation with a detection limit as low as 2.28 nM for NO detection. The high levels of selectivity and sensitivity to NO in complex biological environments can be attributed to the exposed Ni2+ active sites, high ion-electron transport rates of NWs, and the high conductivity of ILs and AuNPs. Furthermore, the IL@Au@MOFNWs offer a biocompatible sensing interface enabling rapid real-time monitoring of NO released from living cells by drug stimulation. Collectively, these results demonstrate that functionalized ultralong MOFNWs exhibit a remarkable ability to quantify NO levels in cells and could therefore provide new potential of this sensor in electrochemical detection of living bodies.

Direct and 2f-wavelength modulation spectroscopy of NO and OCS using an astigmatic multipass cell coupled with a mid-IR 5.2 µm cw-QCL

We developed a mid-IR 2f-wavelength modulation spectroscopy (WMS) detection system combining a continuous wave external-cavity quantum cascade laser (QCL) at 5.2 μm and an astigmatic multipass cell. The high-sensitivity performance of the 2f-WMS system was validated by simultaneously probing the strongest interference-free absorption lines of Λ-doublet components of R (6.5) rotational line in 2Π1/2 magnetic electronic sub-state of nitric oxide (NO) centred at 1900.0706 cm−1 and the R (18) rotational line of carbonyl sulphide (OCS) in the (ν 1 + 2ν 2) combination band centred at 1899.9756 cm−1. We compared the results with the direct absorption spectroscopy and have shown that a detection limit of 300 ppb for NO and 3 ppm for OCS could easily be achieved by the 2f-WMS method with an optical pathlength of 76 m. Hence, we believe that in the future the present QCL based 2f-WMS detection method with high sensitivity and specificity could be deployed for real-time monitoring of NO and OCS in a harsh environment.

Molecularly assembled graphdiyne with atomic sites for ultrafast and real-time detection of nitric oxide in cell assays

Nitric oxide as a signal molecule participates in a variety of physiological and pathological processes but its real-time detection in cell assays still faces challenging because of the trace amount, short half-life and easy conversion to other substances. We report here a rational design by assembling highly π-conjugated and small capacitive gaphdiyne (GDY) with a coordination complex of hemin (HEM) into a molecularly assembled material of GDY/HEM to achieve ultrafast and real-time monitoring of nitric oxide in cell assays. GDY comprising alkynyl C atoms can hybridize with the HEM to enable strong π-π interaction and atomic dispersion of iron sites while avoiding the formation of catalytically inactive dimer for the HEM. These characteristics make the GDY/HEM an excellent sensing material towards nitric oxide, which has an ultrafast response time of 0.95 s, a low detection limit of 7 nM and long linear range up to 151.38 μΜ. The GDY/HEM realizes real-time monitoring nitric oxide released from cancer and normal cells, demonstrating its capability for cell analysis.

117 - Cancer Targeted Nitric oxide Delivery with a Fluorescence Reporter

Nitric oxide (NO) is a gaseous signalling molecule, which is endogenously synthesized by nitric oxide synthase (NOS) enzyme. NO mediates numerous biological processes including vasodilation, respiration, cell migration, immune response and apoptosis. Therapeutic effect of NO in cancer mainly depends on its location, concentration and rate of release. Due to the short half-life of NO, controlled generation of NO at cancer site and real time monitoring of NO is necessary.1 Although a number of methodologies for enhancement as well as detection of NO are available, these events are typically mutually exclusive. Thus, a strategy where a small molecule can generate NO in a controlled and sustained manner to the cancer cells selectively along with a fluorescence reporter would be useful for NO based cancer therapy. Elevated level of oxidative species has been found in numerous cancer cells over normal cells due to the overproduction of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), hydroxyl radical, and superoxide anion.2 Among them, H2O2 is the most stable and it has been used extensively for imaging3 as well as drug delivery4 to cancer cells. Here, we report FLUORO/NO, a new class of triggerable NO donors with an in-built fluorescence reporter. Upon activation by H2O2 in buffer, a nearly quantitative correlation between fluorescence intensity (% 2) and NO generation is observed (Figure 1). When encountered with cellular situations with varying ROS levels, FLUORO/NO is observed to preferentially generate NO in cell lines with elevated ROS levels. Therefore, FLUORO/NO is a convenient TheraNOstic tool to enhance NO selectively in cancer cells and allow real time monitoring of NO release.

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.

Long Term Amperometric Recordings in the Brain Extracellular Fluid of Freely Moving Immunocompromised NOD SCID Mice

We describe the in vivo characterization of microamperometric sensors for the real-time monitoring of nitric oxide (NO) and oxygen (O2) in the striatum of immunocompromised NOD SCID mice. The latter strain has been utilized routinely in the establishment of humanized models of disease e.g., Parkinson’s disease. NOD SCID mice were implanted with highly sensitive and selective NO and O2 sensors that have been previously characterized both in vitro and in freely moving rats. Animals were systemically administered compounds that perturbed the amperometric current and confirmed sensor performance. Furthermore, the stability of the amperometric current was investigated and 24 h recordings examined. Saline injections caused transient changes in both currents that were not significant from baseline. l-NAME caused significant decreases in NO (p < 0.05) and O2 (p < 0.001) currents compared to saline. l-Arginine produced a significant increase (p < 0.001) in NO current, and chloral hydrate and Diamox (acetazolamide) caused significant increases in O2 signal (p < 0.01) compared against saline. The stability of both currents were confirmed over an eight-day period and analysis of 24-h recordings identified diurnal variations in both signals. These findings confirm the efficacy of the amperometric sensors to perform continuous and reliable recordings in immunocompromised mice.

Real-Time Monitoring of Nitric Oxide at Single-Cell Level with Porphyrin-Functionalized Graphene Field-Effect Transistor Biosensor.

An ultrasensitive and highly efficient assay for real-time monitoring of nitric oxide (NO) at single-cell level based on a reduced graphene oxide (RGO) and iron-porphyrin-functionalized graphene (FGPCs) field-effect transistor (FET) biosensor is reported. A layer-to-layer assembly of RGO and FGPCs on a prefabricated FET sensor surface through π-π stacking interaction allowed superior electrical conductivity caused by RGO, and highly catalytic specificity induced by metalloporphyrin, ensuring the ultrasensitive and highly specific detection of NO. The results demonstrated that the RGO/FGPCs FET biosensor was capable of real-time monitoring of NO in the range from 1 pM to 100 nM with the limit of detection as low as 1 pM in phosphate-buffered saline (PBS) and 10 pM in the cell medium, respectively. Moreover, the developed biosensor could be used for real-time monitoring of NO released from human umbilical vein endothelial cells (HUVECs) at single-cell level. Along with its miniaturized sizes, ultrasensitive characteristics, and fast response, the FET biosensor is promising as a new platform for potential biological and diagnostic applications.

Origin of endogenous nitric oxide released in the nucleus accumbens under real-time in vivo conditions.

Nitric oxide (NO), is a simple but multifarious molecule. It is implicated in physiological and pathological processes within the striatum, mainly in the nucleus accumbens (NAc). The aim of the present study was to determine the origin of NO in the NAc of anaesthetized rats by applying various compounds known to modulate the release of NO when applied either systemically or locally. Real-time monitoring of NO was carried out by introducing an amperometric NO sensor into the outer tubing of a push-pull cannula. For local application of substances, the push-pull superfusion technique was used. An overdose of urethane (i.p.) or superfusion of the NAc with tetrodotoxin (TTX) led to a fall of NO release in the NAc. The NO synthase (NOS) inhibitors 7-nitroindazolmonosodiumsalt (7-NINA, neuronal NOS selective) and N-nitro-L-arginine (L-NNA, NOS selective) decreased release of NO when applied i.p. or locally. Superfusion of the NAc with N-methyl-D-aspartate (NMDA) elicited a dose dependent increase of NO release. Combination of an amperometric NO sensor for real-time monitoring of NO release with the push-pull superfusion technique showed that NO released in the NAc is, at least to a great extent, of neuronal origin. The enhanced release of NO elicited by locally applied NMDA demonstrates that activation of NMDA receptors facilitates NO synthesis, thus underlining the functionality of NO targets within the NAc.

Effects of prostaglandin E1 on nitric oxide and oxygen dynamics during rat myocardial ischemia–reperfusion utilizing sol–gel derived microsensors

Prostaglandin E1 (Alprostadil®, PGE1) is often used for patients with critical limb ischemia due to its vasodilator and anti-platelet effects. Although PGE1 is considered to have a cardioprotective effect against myocardial ischemia–reperfusion (IR) injury, its mechanism and correlation with nitric oxide (NO) for cardioprotection are not clear. In this study, we used sol–gel-modified electrochemical NO and O2 microsensors to simultaneously measure the changes in NO level and oxygen tension (pO2) in the myocardium during myocardial IR that were induced by PGE1 pretreatment. Rat hearts were randomly divided into two groups: a control group (n=5) and a PGE1 group (n=5, with PGE1 pretreatment). Myocardium that underwent PGE1 pretreatment (26.0±13.1%, p<0.001) demonstrated more highly reduced endogenous NO production during the ischemic period than that of the control group (86.7±18.5%). After the onset of reperfusion, %NO level in the PGE1 group increased to a maximum of 82.0±6.4 but did not exceed the pre-ischemic basal NO level. However, in the control group, the maximum %NO response (164.9±41.0) on reperfusion was approximately double that of the PGE1 group (p<0.01, n=5). The restoration value of pO2 in the PGE1 group significantly increased and was restored to pre-ischemic level (82.2±21.3%); however, the pO2 of the control group did not increase throughout the reperfusion period (12.3±7.9%, p<0.001). As a result, we suggest that the cardioprotective effect of PGE1 might be attributed to a reduction in excessive NO production during reperfusion. Therefore, simultaneous and real-time monitoring of NO and pO2 dynamics in the myocardium would be effective in evaluating the effects of therapeutic treatments such as drug administration. Also, the reduction in excessive NO release during the early reperfusion period might be helpful as a therapeutic strategy to protect the myocardium from IR injury.

Layer-by-layer assembled gold nanoparticles with a tunable payload of a nitric oxide photocage

We report herein the design, preparation and characterisation of a new, water soluble, nanoplatform for the light-triggered release of nitric oxide (NO). This nanoconstruct has been achieved by exploiting a layer-by-layer approach to assembly a polyelectrolyte modified with a NO photochemical precursor, around citrate stabilized gold colloidal template. Combined spectroscopic and transmission electron microscopy analysis show that the layered hybrid nanoparticles remain stable under physiological conditions without any significant clustering along the different coating processes. The photochemical properties of the NO photocage are well preserved upon its covalent grafting in the polymeric skeleton, before and after the of the metal colloids. The direct and in real time monitoring of NO using an ultrasensitive electrode unambiguously shows the light-stimulated NO release from modified gold nanoparticles and demonstrates that the approach used permits the accurate regulation of the NO reservoir on the nanoparticles surface.

Real time dynamics of nitric oxide during cardiac ischemia-reperfusion of the rat

Nitric oxide (NO) plays important roles in the cardiovascular system by mediating various physiological and pathophysiological processes. However, the role of endogenous NO in ischemia-reperfusion is still controversial. Direct and real-time monitoring of NO is difficult because NO is present only at low concentrations in the body and has a short half-life. Therefore, we utilized a sol–gel derived electrochemical NO microsensor to monitor changes in NO during myocardial ischemia-reperfusion. We also analyzed differences in NO dynamics between intact and hypothermic hearts to investigate the role of endogenous NO formation in the myocardium. A NO sensor was built using a xerogel-modified platinum microsensor and coiled Ag/AgCl reference electrode. Rat hearts were randomly divided into two groups: intact ( n = 6, without hypothermic treatment after harvest) and hypothermic ( n = 6, with hypothermic treatment after harvest) groups. Hearts were placed on a Langendorff apparatus and treated by 40 min of ischemia and 30 min of reperfusion. In the ischemic myocardium, NO showed a time-course dependent change during the 40 min ischemic episode. The restoration concentration of NO was decreased below the pre-ischemic level after myocardial ischemia and early reperfusion. However, myocardium that underwent hypothermic treatment (151 ± 37 nM) released more NO during the ischemic period than that without any treatment (59 ± 15 nM). In addition, the restoration concentration of NO in the hypothermic group (−57 ± 26 nM) was significantly higher than that of the intact group (−170 ± 50 nM, p < 0.05). Endogenous NO formation was observed during ischemic episodes, which is a reaction against ischemia. We inferred that hypothermic treatment for cardioprotection would activate endogenous NO production in the ischemic myocardium. Therefore, promotion of endogenous formation and inhibition of the time course alteration of NO during ischemic episodes might be a helpful therapeutic strategy for protecting the myocardium from ischemic injury.

Eletrodeposited nickel oxide on a film of carbon nanotubes for monitoring nitric oxide release from rat kidney and drug samples

Nickel oxide nanoparticles (NiO-NPs) were electrodeposited on a film of multi-walled carbon nanotubes to improve the electro-oxidation of nitric oxide (NO). The resulting sensor film exhibits excellent electrocatalytic activity towards NO and was used for the construction of an amperometric sensor for NO that was applied to monitoring the release of NO from sodium nitroprusside in rat kidney. Key operational parameters such as the conditions for deposition, kind of electrolyte and pH value were optimized. The nano-structured sensor possesses numerous active sites for oxidation of NO and thus exhibits good performance including wide linearity, simple operation, and good stability. The response to NO is linear in the concentration range from 80.0 nmol·L−1 to 0.117 mmol·L−1, the limit of detection is 20.0 n mol·L−1. The sensor was developed for real-time monitoring of NO.

Real-time monitoring of nitric oxide in diesel exhaust gas by mid-infrared cavity ring-down spectroscopy

We report the accurate and precise measurement of nitric oxide (NO) in automotive exhaust gas by cavity ring-down spectroscopy (CRDS) using a thermoelectrically cooled, pulsed quantum cascade laser (QCL) as a light source. A mid-infrared QCL with a 5.26 μm wavelength was used to detect fundamental vibrational transitions of NO. An effective optical path length of 2.1 km was achieved in a 50 cm long cell using high-reflectivity mirrors. In combination with a particle filter and a membrane gas dryer, stable and sensitive measurement of NO in exhaust gas was achieved for more than 30 minutes with a time resolution of 1 s. The results of this work indicate that a laser based NO sensor can be used to measure NO in exhaust gas over a dynamic range of three orders of magnitude.

Real-Time Monitoring of Nitric Oxide (NO) and pO 2 Levels Under Ischemic Conditions Associated With Small Bowel Ischemia/Reperfusion Injury Using Selective Electrodes for NO and Oxygen Molecules

The present study demonstrated the feasibility of monitoring nitric oxide (NO) and pO 2 levels under ischemic conditions associated with small bowel ischemia/reperfusion (I/R) injury through the use of selective electrodes for NO and oxygen molecules. NO levels gradually increased during ischemia. When reperfusion was started, the NO level decreased suddenly and returned to pre-ischemia values within 10 minutes. After clamping, pO 2 decreased rapidly. When reperfusion was started, pO 2 increased suddenly, returning to pre-ischemia values within 10 minutes. We concluded that it is feasible to monitor NO and pO 2 levels under ischemic conditions of small bowel I/R injury through the use of electrodes selective for NO and oxygen molecules.