OxyLite™ oxygen monitors 1, 2 and 4-channel dissolved oxygen and temperature monitors

The survival of tissues and organs relies on an adequate supply of oxygen. The measurement of tissue oxygen tension (ptiO₂) provides a direct measurement of the balance between oxygen supply (by the blood) and metabolic oxygen consumption (by the tissue), i.e. a readout of oxygen availability at the cellular level. This is in contrasts to spectroscopy (NIRS) techniques, which merely describe haemoglobin oxygenation status.

Our OxyLite™ oxygen monitors will be of interest therefore to life scientists wishing to directly and continuously measure dissolved oxygen in the normal physiological as well as hypoxic ranges, both in experimental in vivo models, or in any number of in vitro applications.

Since 1998, when Oxford Optronix pioneered the commercialization of fibre-optic oxygen micro-sensor technology, the OxyLite™ brand has become established the world over, boasting in excess of 500 peer-reviewed journal citations with hundreds of units sold worldwide.

Blending contemporary design, true plug and play convenience and the very latest in opto-electronic technology, our latest generation OxyLite™ Pro systems provide what is simply the most advanced, accurate and reliable tissue oxygen monitoring platform on the market.

Our fibre-optic sensors leverage state-of-the-art optical fluorescence technology intended for the quantitative measurement of oxygen partial pressure (pO₂) and temperature in tissues, physiological fluids, cell cultures and other in vitro applications. This technology offers key advantages over traditional, polarographic oxygen sensing techniques, making our monitors much easier to use and ideally suited to oxygen measurements in the physiological range, as well as incredibly sensitive under conditions of hypoxia.

Applications include:

• Cerebral oxygen in stroke models
• Tumour angiogenesis and oxygenation
• Vital organ oxygenation during transplantation and shock monitoring
• The importance of oxygen in brain and spinal cord injury
• Tissue flap and wound oxygenation
• In vitro dissolved oxygen in tissue culture, bioreactors, etc.

_{Intended use statement:
OxyLite™ and OxyLite™ Pro are intended for laboratory, industrial and research use only.}

The easiest-to-use dissolved oxygen monitors in the world

No calibration procedures, no sensor drift, no obligatory PC/software interface, integrated temperature compensation, oxygen partial pressure displayed in absolute units of mmHg: our world-renowned OxyLite™ oxygen monitors are simply the most user-friendly oxygen monitors available today, period.

Absolute units of dissolved oxygen

The fluorescence-based technique employed by our oxygen monitors provides an absolute measurement of dissolved oxygen in mmHg or kPa. In vivo this provides a direct readout of oxygen availability to cells and tissue, in contrast to blood oxygen saturation assessment (pulse oximetry), which merely describes the haemoglobin oxygenation status of blood.

Sensitivity and accuracy

Third-generation opto-electronics provide unmatched sensitivity, stability and accuracy in the physiologically relevant pO₂ range (0 – 200 mmHg) and under conditions of hypoxia (0 – 15 mmHg).

No oxygen consumption

Zero oxygen consumption at the point of measurement, thus innately suitable for continuous and absolute oxygen sensing, even under conditions of extreme hypoxia.

Microchip sensors

‘EEPROM’ technology embedded within our purpose-designed connectors provides unsurpassed ease of use and user convenience by completely eliminating all calibration procedures. Simply ‘plug and go’!

Touch-screen display and interface

OxyLite™ Pro models feature a touch-sensitive, high-contrast, 140º viewing-angle screen, which displays real-time data in both digital and graphical (trace) formats, and provides access to instrument/user settings.

Built-in temperature compensation

Automatic temperature compensation of the pO₂ measurement through optional, integrated temperature sensors.

Versatility

Full support for both in vivo (tissue) pO₂ applications AND measurement of dissolved oxygen in vitro (e.g. hypoxic cell culture, tissue constructs, bioreactors and more).

Minimally invasive for in vivo applications

Oxygen sensor diameters range from approximately 230 µm – 750 µm to suit a host of tissue monitoring applications and cause minimal tissue disruption in use.

MRI compatibility

Dedicated sensor types provide support and compatibility for magnetic resonance imaging (selected sensor types only).

Multi-channel productivity

The OxyLite™ Pro is available as a 2-channel model or, uniquely, as a 4-channel device (OxyLite™ Pro XL) capable of driving up to 4 sensors simultaneously. This provides the flexibility to suit all needs, including the simultaneous monitoring of oxygen from multiple tissue sites (e.g. comparison of pathological versus control tissue sites), or multiple in vitro samples.

Upgradeable

The OxyLite™ Pro 2-channel model can be factory upgraded to the 4-channel model (OxyLite™ Pro XL).

Single-sensor multi-parameter monitoring

Our OxyLite™ oxygen monitors can be used alongside our OxyFlo™ blood flow monitors in a stack arrangement providing simultaneous tissue oxygen and blood flow measurements from unique 'triple' parameter combined sensors.

USB digital output

Our entire range of tissue monitoring devices include a dedicated USB output that supports direct streaming of real-time recordings to a PC running the popular LabChart® Pro* charting software by ADInstruments. After installing a complimentary add-on, LabChart will automatically identify the specific type and model of Oxford Optronix monitor and pre-load all the necessary configuration and channel settings, providing the ultimate in ‘plug and play’ convenience. For researchers wishing to make multi-parameter measurements, the add-on supports multiple Oxford Optronix devices at the same time. Data acquisition and recording just got a whole lot easier!

*LabChart version 8.0.4 or later required; PC/Windows only

Analogue outputs

Continuous data recording to PC or Mac platforms is also supported via standard analogue data outputs offering compatibility with third party data recording solutions.

2-year product warranty

Our monitors are provided with a comprehensive 2-year manufacturer’s warranty, covering defects in material or in workmanship. Optional extended warranty packages including preventative maintenance servicing are also available for additional peace of mind.

A single, combined oxygen/temperature sensor was used to continuously measure hind leg muscle tissue pO₂ and temperature during repeated phases of contraction stimulation. The upper trace shows pO₂ in units of mmHg; the lower trace shows temperature in units of degrees C.

What physiological parameters does OxyLite™ measure?
Our oxygen monitors are intended to measure the partial pressure of oxygen (pO₂) in aqueous conditions (i.e. conditions of 100% relative humidity). The oxygen partial pressure is also often referred to as ‘dissolved oxygen’ and is very much distinct from the measurement of haemoglobin oxygen saturation using spectroscopic techniques (e.g. a pulse oximetry). Our OxyLite™ monitors also optionally provide a real-time readout of temperature from the sensor tip.

How do pO₂ measurements differ from oxygen saturation measurements?
The fluorescence-based technique employed by our oxygen monitors provides an absolute measurement of dissolved oxygen in mmHg or kPa. In tissue monitoring applications this provides a direct readout of the balance between oxygen supply (by the blood) and oxygen consumption (by tissue/cell metabolism), i.e. a readout of oxygen availability to cells and tissue. This contrasts to blood oxygen saturation assessment (pulse oximetry), which merely describes the haemoglobin oxygenation status.

What makes the OxyLite™ unique?
A number of key features make our oxygen monitors stand out. Most notable are unmatched ease of use thanks to our proprietary ‘EEPROM’ connectors, quality and measurement accuracy. OxyLite™ also uniquely supports simultaneous measurement of oxygen and blood perfusion in tissues when used in a stack configuration with its OxyFlo™ blood flow monitor counterpart.

What are the typical applications for the OxyLite™?
Our oxygen monitors have proved popular in applications covering such disciplines as tumour research, cerebral monitoring, free-flap/pedicle-flap transfer surgery, transplantation surgery and vital organ monitoring, peripheral vascular disease research and in a variety of specialist in vitro applications including hypoxic cell culture, tissue engineering and bioreactor monitoring.

How do your oxygen sensors work?
Our oxygen sensors are based on fluorescence quenching and fibre-optic technology. Short pulses of LED light are transmitted along the fibre optic sensor to excite a platinum-based fluorophore bonded to the sensor tip. The resulting emission of fluorescent light, quenched by the presence of oxygen molecules is detected by the instrument. The instrument measures the lifetime of fluorescence, which is inversely proportional to the concentration of dissolved oxygen and is interpreted to provide an absolute value for oxygen in mmHg or kPa.

What are the advantages of oxygen sensing using fluorescence technology?
The novel fluorescence-based technology employed in our sensors and monitors offers several key advantages over devices based on polarographic electrodes. These include an absence of oxygen consumption (allowing continuous oxygen measurement, even in hypoxic conditions), factory sensor pre-calibration and calibration stability and maximal sensitivity in the physiological oxygen range (0 – 200 mmHg). A number of our fibre-optic sensors also offer MRI-compatibility.

What procedures are required to calibrate your oxygen sensors?
None! Our oxygen sensors are shipped factory pre-calibrated thereby eliminating time consuming pre- or post-calibration procedures. The calibration information (unique per sensor) is stored on an EEPROM chip within the sensor connector and is read by the monitor within seconds upon connection. Our oxygen sensors are therefore fully ‘plug and go’.

What is the measurement range of your oxygen sensors?
Our oxygen sensors are intended for the measurement of dissolved oxygen (pO₂) in the typical physiological range. The officially supported range is 0 – 200 mmHg (0 – approx. 25 % oxygen). Maximum sensitivity is observed between 0 – 150 mmHg.

What are your oxygen sensors made of and how large are they?
All our oxygen microsensors are constructed from optical fibres with an outside diameter of 230 microns. Sensors are provided a number of formats, including minimally invasive ‘bare-fibre’ format (with and without integrated temperature sensor), in a robust needle-encased format (approx. diameter 650 microns), or in a specialist format for large area sensing (typically in large animal models) (approx. diameter 650 microns). Optical fibres are protected in PVC or silicone sleeving and are typically 2.5 m in length. See here for a full list of available oxygen sensor types.

What are the advantages of fibre-optic sensors?
The use of fibre-optic sensors allows them to be minimally invasive, to be factory recalibrated, to offer MRI-compatibility, as well as to be light weight and physically flexible.

Do your oxygen monitors support the use of multiple sensors at the same time?
Yes, the OxyLite™ Pro is a two-channel monitor, while the OxyLite™ Pro XL is a four-channel monitor capable of simultaneously driving and reading from up to 4 oxygen sensors simultaneously. This allows simultaneous sampling from several samples in vitro, or the collection of physiological data from up to four separate tissue sites at the same time. The latter may be useful when comparing pathological versus control tissue sites. The ability to monitor from more than one tissue site also provides unique possibilities for studying spatial tissue oxygen variability, or, conversely, can be useful in mitigating for natural tissue oxygen variability by allowing multi-site signal averaging.

Are your sensors supplied sterile?
No. While we manufacture our oxygen sensors in a clean room facility, they are not supplied sterile. Oxygen sensors can however be disinfected using 70% IMS or ethanol. Note that neither our oxygen sensors, nor our oxygen monitors possess CE or FDA regulatory approval for use in human subjects.

Can the OxyLite™ or the OxyLite™ Pro models be used for in vitro oxygen measurements?
Yes! Our oxygen monitors and sensors are ideally suited for in vitro applications where expected oxygen levels fall within the supported range of the instrument (0 – 200 mmHg, or 0 – approx. 25% oxygen). Their small size and fibre-optic construction mean that our oxygen sensors are particularly well suited to applications such as hypoxic cell culture, tissue engineering and/or bioreactor surveillance.

Are your oxygen sensors suited to measuring arterial oxygen (paO2) or venous oxygen (pvO2)?
Yes, provided oxygen concentrations fall within the 0 – 200 mmHg supported dynamic range, oxygen can be measured continuously from whole blood in situ. Extended exposure may result in clotting around the sensor tip, depending on the presence or absence of anticoagulant.

Why do you offer oxygen sensors with integrated temperature?
Fluorescence-based oxygen sensing shows a small degree of sensitivity to temperature changes. For optimal accuracy, our oxygen monitors can therefore use a continuous temperature input (provided by the thermocouple) to automatically compensate the oxygen measurement. The temperature reading is also available as an output where temperature is a desirable parameter in its own right.

What is the supported temperature range for your oxygen sensors?
The supported temperature range is 0 – 50 degrees Celsius. Effective pO₂ signal temperature compensation has been tested over the range 25-44 degrees Celsius.

What is the sampling volume of your pO₂ sensors?
The surface area of the tip of our fibre-optic oxygen sensors is estimated to be approx. 0.25 mm2. In a typical tissue this surface area may correspond to direct exposure to around 1000 cells. On the basis that several cell layers are likely to contribute to the dissolved oxygen diffusing in and out of the sensor tip, and assuming typical cell volume (size) and tissue cell densities, the volume of tissue sampled by our oxygen sensors in vivo is estimated to be in the region of 0.5 – 1 mm3.

Do your oxygen monitors possess regulatory approval for clinical use?
No. At this time our oxygen monitors and sensors do NOT possess CE or FDA regulatory approvals for use on human subjects.

Do you offer on-site demonstrations?
Yes, depending on geographical location we will try to arrange for an on-site demonstration of our products by an experienced product specialist. Ideally this will involve a full simulation of your application in order to maximize the benefit of the demonstration. On-site demonstrations are usually free of charge and can typically be arranged at 2 – 8 weeks notice. Alternatively we can also arrange for a limited free trial of our monitors and sensors.

“Our group has successfully applied OxyLite needle probes to measure changes in tissue oxygenation in response to drug treatment. OxyLite has allowed us to collect important mechanistic data to identify the mechanism of these drug treatments in laboratory animals. We greatly appreciate having a calibrated method like the OxyLite probe technology available that allows the collection of accurate, real-time physiological data from live animals.”
Dr Thies Schroeder, Duke University Medical Center, Department of Radiation Oncology, Durham NC, United States

“Your equipment has taken me to some weird and wonderful places and contributed to about a dozen original articles over the last decade.”
Dr. Roger Evans, Monash University, Department of Physiology, Melbourne, Australia

“I use the BF/OT/E PO2 E-series sensor to measure PaO2 in vivo in invertebrates during external environmental fluctuations in PO2. Due to the accuracy and reliability of the PO2 probes we can design experiments that provide real time measurements of PO2 during changes in environmental variables and more accurately link this to behavioural responses. During the experimental set up the staff at Oxford Optronix were always on hand to help out with any technical queries and even visited the laboratory to check out the experimental set up and ensure the probes were working. I would recommend Oxford Optronix to anyone with an interest in measuring PO2 and temperature in marine science.”
Dr Elizabeth Morgan, National Oceanography Centre, University of Southampton, UK

Our OxyLite™ and OxyLite™ Pro oxygen monitors are employed the world over, boasting an extensive journal citation record across a wide range of research applications.

Selected recent journal articles:

Marina N et al. (2020). Astrocytes monitor cerebral perfusion and control systemic circulation to maintain brain blood flow. Nat Commun 11(1), 131

Sheng T, Ong YH, Guo W and Zhu T (2020). Reactive oxygen species explicit dosimetry to predict tumor growth for benzoporphyrin derivative-mediated vascular photodynamic therapy. J Biomed Opt. 25(6), 1-13

Gehrung M, Bohndiek SE and Brunker J (2019). Development of a blood oxygenation phantom for photoacoustic tomography combined with online pO2 detection and flow spectrometry. J Biomed Opt. 24(12), 1-11

Tran CHT, George AG, Teskey GC and Gordon GR (2019). Seizures cause sustained microvascular constriction associated with astrocytic and vascular smooth muscle Ca2+ recruitment. bioRxiv http://dx.doi.org/10.1101/6440...

Baark F, Shaughnessy F, Pell VR, Clark JE, Eykyn TR, Blower P and Southworth R (2019). Tissue acidosis does not mediate the hypoxia selectivity of [64Cu][Cu(ATSM)] in the isolated perfused rat heart. Sci Rep 9(1), 499

Bodo S, et al. (2019). Single-dose radiotherapy disables tumor cell homologous recombination via ischemia/reperfusion injury. J Clin Invest. 129(2), 786-801

Oxygen sensors for OxyLite™

A wide selection of oxygen sensors is available to suit both physiological (in vivo) monitoring and a variety of in vitro applications. Sensors featuring integrated thermocouples support automatic temperature-compensation of oxygen readings. Oxygen sensors are supplied in sealed Tyvek® pouches.

Bare-Fibre Oxygen Sensors

Needle Oxygen Sensors

Large Area Oxygen Sensors

Implantable Oxygen Sensors

Intended use statement:
OxyLite™ and OxyLite™ Pro are intended for laboratory, industrial and research use only.