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.

  • 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, so they are ready to use right out of the box
  • Flexible flow rate range: 5-500 mL/min
  • Luer-lock connectors make it easy to install the flow cells, regardless of tubing size
  • Powerful DOTS Software for easy sensor handling and real-time data visualization

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)
washington_state_university_logo

How It Works

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

What Is a Flow Cell?

Flow-Cell-Bioreactor-Closed-Loop 2

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?

flow-cell-internal-explanation-no-background2

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

pH_flowcell_sensing

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

SBI-Sensor-PH-O2-Flow-Cell-Graphics-WEB3a

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.

 

Hardware & Software Components

Flow Cell

flow-cells-circle-background

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

fiber-optic-sensor-circle-background

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

SBI-Icon-dots-software-computer-2

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. 

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

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

Customer Success Stories

ph-do-graph
“Incorporating SBI’s pH and DO flow cells into our system removed the need for manual sampling, saving us time, reducing the risk of contamination, and providing information on how the cells are growing even when we are not in the lab. With availability of this more detailed view of our culture, we can make informed improvements to our cell expansion process.”

-Kitana Manivone Kaiphanliam (Washington State University)
washington_state_university_logo

Want To Connect The DOTS In Your Bioprocessing?