Real-Time in Vivo Simultaneous Measurements of Nitric Oxide and Oxygen Using an Amperometric Dual Microsensor

Abstract

This paper reports a real-time study of the codynamical changes in the release of endogenous nitric oxide (NO) and oxygen (O(2)) consumption in a rat neocortex in vivo upon electrical stimulation using an amperometric NO/O(2) dual microsensor. Electrical stimulation induced transient cerebral hypoxia due to the increased metabolic demands that were not met by the blood volume inside the stimulated cortical region. A NO/O(2) dual microsensor was successfully used to monitor the pair of real-time dynamic changes in the tissue NO and O(2) contents. At the onset of electrical stimulation, there was an immediate decrease in the cortical tissue O(2) followed by a subsequent increase in the cortical tissue NO content. The averages of the maximum normalized concentration changes induced by the stimulation were a 0.41 (±0.04)-fold decrease in the O(2) and a 3.6 (±0.9)-fold increase in the NO concentrations when compared with the corresponding normalized basal levels. The peak increase in NO was always preceded by the peak decrease in O(2) in all animals (n = 11). The delay between the maximum decrease in O(2) and the maximum increase in NO varied from 3.1 to 54.8 s. This rather wide variation in the temporal associations was presumably attributed to the sparse distribution of NOS-containing neurons and the individual animal's differences in brain vasculatures, which suggests that a sensor with fine spatial resolution is needed to measure the location-specific real-time NO and O(2) contents. In summary, the developed NO/O(2) dual microsensor is effective for measuring the NO and O(2) contents in vivo. This study provides direct support for the dynamic role of NO in regulating the cerebral hemodynamics, particularly related to the tissue oxygenation.

In vivo biosensing via tissue-localizable near-infrared-fluorescent single-walled carbon nanotubes

“…The in vivo detection of nitric oxide (NO) is utilized as a model since it is a free-radical involved in diverse biological processes, such as apoptosis, neurotransmission, blood pressure control and innate immunity 20 and has not been probed in intraperitoneal tissues. Current technology allows for in vivo NO detection through an electrochemical probe surgically implanted in a rat's brain 21 , but does not permit long term or non-invasive NO detection. Of critical importance to NO function is its steady-state concentration in tissues, with biologically relevant concentrations ranging over three orders-of-magnitude.…”

Recent Developments in Electrochemical Sensors for the Detection of Neurotransmitters for Applications in Biomedicine

“…Nitric oxide (NO) is a gaseous diatomic molecule possessing cytotoxic and cytoprotective, properties depending upon the physiological concentrations (Park 2010). NO is known to have an important regulatory role as a neurotransmitter in central nervous system (Jo 2011).…”

Real-Time Detection of Nitric Oxide Release in Live Cells Utilizing Fluorinated Xerogel-Derived Nitric Oxide Sensor

“…In general, amorphous, hydrophobic fluoropolymers are highly permeable to many gaseous species including oxygen, nitric oxide, carbon dioxide, ammonia, and volatile organic compounds [12,35]. Indeed, a microporous poly(tetrafluoroethylene) (PTFE) film has been extensively employed to improve a Clark-type oxygen sensor as a gas-permeable membrane [36,37]. The PTFE membrane effectively prevented the biofouling at the interface between the sensor surface and the biological samples (e.g., blood), while enabling high permeation and rapid diffusion of oxygen [36].…”

“…Indeed, a microporous poly(tetrafluoroethylene) (PTFE) film has been extensively employed to improve a Clark-type oxygen sensor as a gas-permeable membrane [36,37]. The PTFE membrane effectively prevented the biofouling at the interface between the sensor surface and the biological samples (e.g., blood), while enabling high permeation and rapid diffusion of oxygen [36]. However, the fabrication of such sensors remains complicated.…”