Measure and Visualize Oxygen, pH or Carbon Dioxide Distributions in 2D for Life Science Research

Software

All software versions, whether for O₂, pH or CO₂ imaging, have the same user interface, so you only have to get familiar with it once to be able to work with all. The software allows controlling the image recording process, and assists image processing and evaluation. An easy to use camera controlling user interface manages image acquisition and storage. Measurements which belong together can be organized in user defined sessions as separate folders and annotated with a free text comment. Acquired images can be single images or atomatically recorded time series.

Benefits:

• Display the sensor response in false color image
• Display the acutal pixel information
• Display ROI statistics of user defined polygon ROIs
• Interactive x- and y-axis profiles
• Z-axisprofiles for plotting ROI average at defined coordinates
• Follow kinetics through a time series and display as 2D-plots
• Side-by-side image comparison of selected images
• Alpha blending of false color sensor response with color image

The Smart Measurement Method

Fluorescence Ratiometric Imaging (FRIM) is a method for reading out the signal of a fluorescent chemical optical sensor. Ratiometric measuring compensates most of the common interferences, e. g. inhomogeneous lightfields. An optical sensor foil contains an analyte sensitive dye and a reference dye which are immobilized in a permeable polymer matrix layer. The indicator dye is emitting red or green fluorescence, depending on the analyte and respective sensor foil type, which is dynamically quenched by the analyte while the reference dye is giving a constant green or red light signal respectively. These emissions meet exactly the red and green channel sensitivity of a color RGB chip.

Determination of Oxygen Gradients in Cell Culture and Engineered Tissue

Monitoring oxygen supply in cell culture or engineered tissue is very important. Especially cells towards the center of a culture can be subject to low oxygen levels. With VisiSens continuous, high-resolution oxygen measurements over cross sections of samples can be performed. The sensor foils can easily be applied in test or cultivation vessels, and samples are immobilized on top of the sensor. Measurements are taken non-invasively from outside the vessel, which reduces the risk of contamination. With its small footprint the VisiSens system can be mounted inside an incubator without any problems. Detecting oxygen gradients will allow taking measures, or apply new methods to avoid cell death due to hypoxia.

In upcoming studies hydrogels will be tested on their suitability as cell carriers in regenerative therapy. Oxygen releasing additives should sustain constant oxygen supply to the cultured precursor cells. VisiSens will be used to monitor the continuity and homogeneity of oxygen release and the actual oxygen supply of the cells.

2D Imaging in Microfluidic Devices

Microfluidic devices are an emerging technology in the Biotech sector. Due to many advantages as e. g. low fluid volumes, faster analysis and response times which allow better process control, and the compactness of the chips which enables massive parallelization, these devices gain in importance. With VisiSens it is possible to continuously monitor the important culture parameters oxygen, pH, or CO₂ now in high resolution over the whole chip surface. During development, this allows determining suitable culture device materials, e. g. for their oxygen permeability, according to application and cell line. Oxygen, pH, or CO₂ monitoring with VisiSens will improve microfluidic device functionality even further, and it exhibits superior properties compared to similar sensing products.
C. Ochs, et al.: Cellular Oxygen Consumption in Microfluidic Devices, Oxygen in Action Competition Report, 2012

pH Imaging in Skin Models

pH imaging is an innovative method for investigating complex disease processes like e. g. wound healing and tumor biology. The pH of the wound fluid is known to greatly affect the healing process. Measurement techniques used so far have been very difficult to implement. The two-dimensional visualization of pH dynamics with VisiSens now allows monitoring spatially heterogeneous processes on skin models, which is a great advantage compared to single-point measurements with probes. Another future application of pH imaging will be tumor research giving insight in spatial and temporal changes of tumor metabolism.