Simultaneous carbon dioxide and oxygen sensing

Jun 21, 2006

Breathing. Birds, do it, bees do it, even educated trees do it. But, only plants can make sugars from the carbon dioxide byproduct and at the same time expel oxygen during photosynthesis. This amazing skill has intrigued scientists for decades but separating out the carbon dioxide inputs and outputs while keeping tabs on oxygen levels has always proved difficult.

Now, a new type of chemical sensor, described in the journal Advanced Materials, could change all that. The sensor developed by Otto Wolfbeis and colleagues at the Institute of Analytical Chemistry, Chemo- and Biosensors at the University of Regensburg, Germany, will allow clearer insights into plant respiration and photosynthesis. It could also have application in the food and drink industry as well as in the biotech industry where fermentation and related plant processes are important.

Woflbeis explains that in order to unravel the intricacies of photosynthesis and respiration, two of the most important biochemical processes, scientists have to be able to measure carbon dioxide and oxygen at the same time. He and his team have now found a way to side-step the interference from which all previous sensors suffer. The team first create nanoparticles carrying a fluorescent group that react to light and glow only when they are in contact with carbon dioxide molecules.

These nanoparticles are then embedded in a layer of polymer resin. A second compound that does the same in the presence of oxygen molecules is embedded in a second layer of polymer and the two films sandwich between them a layer of an organometallic compound containing the heavy metal iridium. This layer produces a reference signal for the detection of fluorescence triggered by the two gases. Importantly, however, it is impermeable to oxygen molecules and so its light is not quenched by interference from oxygen.

A blue light-emitting diode (LED) then provides the stimulation for the two sensitive layers to produce light, but only in the presence of their respective gases. A tiny photodetector can then measure the wavelength of light emitted, which is different from each sensor molecule. The strength of the emitted light at each wavelength correlates with the concentration of each of the two gases.

The team tested their sensor over a wide range of different carbon dioxide and oxygen concentrations produced by a growing microbial culture and found it to operate with a remarkable ±5% accuracy at concentration levels expected for real experiments. At much higher but unrealistic concentrations, accuracy deviated only by as much ±10%. Because the device is designed to be reusable rather than a one-shot dip test, the team tested its response after several hundred runs and found it to still be working at these levels of accuracy after 800 runs.

They anticipate that their composite material will become a powerful tool in biological, biotechnological, and medical research. The simultaneous sensor could also have applications in environmental monitoring of sea water and sewage and in medical diagnostics, where blood gas levels are important to understanding the progression of certain diseases.

The research will be commercialized by Presens GmbH.

“It is likely to become a powerful tool in combinatorial microbiology, in cell-based screening for drugs, and in biomonitoring in general," Wolfbeis explains. "In combination with fiber optic microsensors, in vivo sensing of oxygen and carbon dioxide should be possible.”

Citation: Otto Wolfbeis, Composite Material for Simultaneous and Contactless Luminescent Sensing and Imaging of Oxygen and Carbon Dioxide, Advanced Materials 2006, 18, No. 12, 1511–1516, doi: 10.1002/adma.200600120

Source: Advanced Materials

Explore further: Artificial muscles get graphene boost

Related Stories

Sunfire, Audi en route to synthetic fuel of future

Apr 28, 2015

How are scientific minds doing in coming up with a synthetic fuel as a viable alternative to petroleum? For some engineers, this is a long-held dream they refuse to dismiss. A Dresden-based company, sunfire, ...

How olive oil is processed

May 15, 2015

The olive tree is native to the Mediterranean basin. Archeological evidence shows that olive oil was produced as early as 4000 BC. Besides food, olive oil was used historically for medicine, lamp fuel, soap, ...

Does the red planet have green auroras?

May 14, 2015

Martian auroras will never best the visual splendor of those we see on Earth, but have no doubt. The red planet still has what it takes to throw an auroral bash. Witness the latest news from NASA's MAVEN ...

Recommended for you

Artificial muscles get graphene boost

May 22, 2015

Researchers in South Korea have developed an electrode consisting of a single-atom-thick layer of carbon to help make more durable artificial muscles.

How to make continuous rolls of graphene

May 21, 2015

Graphene is a material with a host of potential applications, including in flexible light sources, solar panels that could be integrated into windows, and membranes to desalinate and purify water. But all ...

Carbon nanothreads from compressed benzene

May 20, 2015

A new carbon nanomaterial – the thinnest possible one-dimensional thread that still retains a diamond-like structure – was created by the controlled, slow compression and decompression of benzene. The ...

Printing 3-D graphene structures for tissue engineering

May 19, 2015

Ever since single-layer graphene burst onto the science scene in 2004, the possibilities for the promising material have seemed nearly endless. With its high electrical conductivity, ability to store energy, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.