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Overview

Use flow cells to monitor pH and dissolved oxygen when standard probes are not an ideal fit. Simply connect the flow cells directly into your flow loops (e.g., feeding, sampling or harvesting flow lines for bioreactors) and start measuring. Detect changes in environmental conditions early and ensure a healthy cell culture with around-the-clock monitoring of these critical process parameters.

 

Key Features

  • pH and DO ranges for a variety of applications

    • pH ranges: 5-7, 6-8, 7-9

    • DO range: 0-50% O2  (gas), 0-100% O2  (liquid) 

  • Factory-calibrated and pre-sterilized for immediate use
  • Flexible flow rate range: 1-500 mL/min

Benefits

  • Save hours of manual hands-on time for probe setup, calibration, and conditioning
  • Free up valuable port space for other uses
  • Ideal for use with perfusion bioreactors, custom benchtop bioreactors, and small-scale fermenters

Current Bioreactor Challenges

Standard Probes are Cumbersome
  • Require time and money for repeated calibration and sterilization
  • Block bioreactor ports
Custom or Unique Systems
  • Vessels with low volumes make offline sampling difficult
  • Systems not compatible with standard probes require alternative measuring solutions

How It Works

The technique for optical pH and DO monitoring is based on the principle of spectroscopy.

What Is a Flow Cell?

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The flow cell is integrated into a flow loop. Chemosensors containing luminescent dye indicators are embedded in a matrix and held inline by the flow cell. The sample travels through the flow cell, passing over the chemosensor. A fiber optic cable is fed into the top of the flow cell, which transmits light between the chemosensor and the fiber optic sensor.

How Does Optical Sensing Work?

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The sensor emits a red light (orange-red at a wavelength of 610-630 nm), exciting the chemosensors which show luminescence in the near infrared region (NIR, 760-790 nm). Depending on the molecules present in the solution, the amount of luminescence changes. The sensor measures this phase shift which is then calculated into the relevant parameter.

pH Sensing Principle

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The chemosensor contains both a pH-sensitive indicator and a pH-insensitive reference dye.

At higher pH levels, the pH indicator dye is de-pronated. When the deprotonated chemosensor is excited via red light transmitted from the fiber optic sensor, the luminescence of the pH-sensitive indicator is quenched and only the NIR emission is measured. As the pH lowers, the sample becomes more acidic and the pH indicator becomes protonated. In this state, when the sensor emits red light, the indicator emits bright NIR luminescence.

Dissolved Oxygen (DO) Sensing Principle

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This chemosensor contains an oxygen-sensitive indicator. 

When the sensor emits red light, the indicator shows bright luminescence in the NIR range. At low concentrations of dissolved oxygen, there is less collision between oxygen molecules and the indicator dye, allowing for a brighter emission of NIR light. As the oxygen concentration increases, the rate of collision also increases. This collision quenches the luminescence of the oxygen-sensitive indicator, reducing the intensity of NIR-emission.

Application Data & Results

Explore applications in real-world situations. Looking for something specific? Contact us to see data for your organism and application.

dissolved-oxygen-bioreactor

CD8 Cytotoxic T Cells, Modified-COBE® Benchtop Centrifugal Bioreactor, 

Informed Bioprocess Insights in Real-time

Improve your bioprocess with real-time information. Dissolved oxygen data showed an average of 5% higher levels than those anticipated by the kinetic model (based on oxygen consumption rates from static culture studies). This outcome suggests that cells might not be using oxygen as rapidly as previously believed. It raises the possibility that the unique dynamics within the bioreactor, such as centrifugal and fluid forces, could be influencing the oxygen consumption patterns of the cells.

Read the case study →

Want to see data for your organism or application?

We have tested over 100 microorganisms for more than 50 different applications with our technology.

Speak With An Expert

 

Hardware & Software Components

Flow Cell

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Single-use flow cells with integrated chemosensors for pH or dissolved oxygen (DO). Each flow cell comes factory-calibrated and pre-sterilized so it is ready to use right out of the box. Luer-lock connectors make is easy to fit to any sized tubing. Combine pH and DO flow cells with a luer-luer adapter and measure both in the same flow loop simultaneously. 

Fiber Optic Sensor

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Consists of an LED which excites the chemosensor and a photodiode that detects the emission. Light is transmitted between the sensor and the flow cell via a fiber optic cable. The sensor collects the data from all monitored flow cells and sends it to the DOTS Software.

Available in single channel for measuring only pH or DO, or dual channel for measuring both parameters at the same time.

DOTS Software

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DOTS Software, when paired with a sensor, allows you to monitor critical parameters while your experiment is running. Personalized dashboards allow you to easily visualize data while experimental control features make important information such as calibration offsets and environmental compensation values (temperature, relative humidity, atmospheric pressure and others) easy to include. 

What Our Customers Are Saying

"Having an integrated oxygen flow cell made all the difference in getting our cell expansion culture to work. The consistent real-time data showed us we needed to provide a better oxygenation system for successful cellular growth."

-Dr. Bernard J. Van Wie (Washington State University)
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Specifications

Measurement Type Liquid – pH
Measurement Range 5-7 pH, 6-8 pH, 7-9 pH
Response Time (t90)

 Flow >10 mL/min <90 sec

Flow <10 mL/min <120 sec
Drift <0.005 per day at 25°C
Shelf Life 1 year in original packaging at room temperature
Recommended Flow Rate 1-500 mL/min
Temperature Range  0-50°C
Pressure Range 0-2 bar
Cross Sensitivity  Organic solvents, charged surfactants
Accuracy  +/- 0.05 (after 2-pt calibration)
Resolution  0.003
Detection Limit  <2 pH, >11 pH
Measurement Type Gas – % O2 Liquid – Dissolved Oxygen
Measurement Range 0-50% O2 0-250% air saturation
Response Time (t90) <10sec

Flow  >10 mL/min <20sec
Flow  <10 mL/min <30sec
Lifetime 10,000,000 data points
Shelf Life 3 years in darkness at room temperature
Recommended Flow Rate 1-500 mL/min
Temperature Range  0-50°C
Pressure Range 0-2 bar
Cross Sensitivity Organic solvents, bleach
Accuracy At 1% O2: +/- 0.02%
At 20% O2: +/- 0.2%		 At 5% air saturation: +/- 0.1%
At 95% air saturation: +/- 1%
Resolution At 1% O2: 0.01%
At 20% O2: 0.05%		 At 5% air saturation: +/- 0.05%
At 95% air saturation: +/- 0.25%
Detection Limit 0.02% O2 0.1% air saturation

Compatible Laboratory Infrastructure

  • Perfusion bioreactors, custom benchtop bioreactors, and small-scale fermenters

  • On-line flow loops

    • Harvest lines, sampling lines, media in/out flow lines, waste removal lines

Our team of application scientists will work with you to ensure that our flow cells fit your specific application. 

  • Cell culture expansion

  • Process characterization

  • Bioprocess quality control

  • Harvest of cellular metabolic products

  • Early contamination detection based on shifts in pH or DO levels

Resources

Specifications - pH
Measurement Type Liquid – pH
Measurement Range 5-7 pH, 6-8 pH, 7-9 pH
Response Time (t90)

 Flow >10 mL/min <90 sec

Flow <10 mL/min <120 sec
Drift <0.005 per day at 25°C
Shelf Life 1 year in original packaging at room temperature
Recommended Flow Rate 1-500 mL/min
Temperature Range  0-50°C
Pressure Range 0-2 bar
Cross Sensitivity  Organic solvents, charged surfactants
Accuracy  +/- 0.05 (after 2-pt calibration)
Resolution  0.003
Detection Limit  <2 pH, >11 pH
Specifications - DO
Measurement Type Gas – % O2 Liquid – Dissolved Oxygen
Measurement Range 0-50% O2 0-250% air saturation
Response Time (t90) <10sec

Flow  >10 mL/min <20sec
Flow  <10 mL/min <30sec
Lifetime 10,000,000 data points
Shelf Life 3 years in darkness at room temperature
Recommended Flow Rate 1-500 mL/min
Temperature Range  0-50°C
Pressure Range 0-2 bar
Cross Sensitivity Organic solvents, bleach
Accuracy At 1% O2: +/- 0.02%
At 20% O2: +/- 0.2%		 At 5% air saturation: +/- 0.1%
At 95% air saturation: +/- 1%
Resolution At 1% O2: 0.01%
At 20% O2: 0.05%		 At 5% air saturation: +/- 0.05%
At 95% air saturation: +/- 0.25%
Detection Limit 0.02% O2 0.1% air saturation
Compatibility

Compatible Laboratory Infrastructure

  • Perfusion bioreactors, custom benchtop bioreactors, and small-scale fermenters

  • On-line flow loops

    • Harvest lines, sampling lines, media in/out flow lines, waste removal lines

Applications

Our team of application scientists will work with you to ensure that our flow cells fit your specific application. 

  • Cell culture expansion

  • Process characterization

  • Bioprocess quality control

  • Harvest of cellular metabolic products

  • Early contamination detection based on shifts in pH or DO levels

Resources

Resources

Customer Success Stories

dissolved oxygen graph

Integrated dissolved oxygen flow cells helped optimize a centrifugal bioreactor (CBR) designed to maximize cytotoxic T lymphocyte (CTL) production for use in immunotherapy treatments.

washington_state_university_logo
Read the full story

Want To Connect The DOTS In Your Bioprocessing?

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