Oxygen is indispensable for most living beings. This is also valid for humans. Only if enough oxygen is available, the respiration and the metabolism are guaranteed in every cell. To better understand both key processes – respiration and metabolism – and their malfunctionings, the research examines the oxygen distribution and the oxygen consumption in the cells. Thus "maps" or pictures of the oxygen distribution would be an important step. Besides, with exisiting measuring methods the researchers reached their limits in the last decades. Therefore research increasingly works with molecular indicators and sensors which change their colour in the presence of oxygen. Such indicators can be observed in the cells with the help of a microscope, however, have the disadvantage that they bind to cell components what complicates the measurement or makes impossible in the worst case.
Picture Source: Chemical Science
Now researchers of the university of Regensburg around Prof. Dr. Otto Wolfbeis and Dr. Hans-Heiner Gorris of the institute of analytic chemistry, Chemo-and bioanalytics have managed in this connection an important breakthrough. The scientists succeeded in enclosing a sensitive oxygen indicator in small globules of polystyrene, a special plastic. Though the globules are permeable for oxygen, they protect the indicators against the influence of the cell components. They are taken up by cells and afterwards can be observed under the microscope.
For her investigations the chemists placed another dye in the globules which is insensitive to oxygen and could serve therefore as a reference. With the comparison between oxygen indicator and authoritative colouring the researchers could carry out the standardised measurements which were insensitive to external influences.
An other specific feature of the globules consists in the fact that the oxygen indicator can be taken up merely on the red canal of a digital colour camera RGB, while the authoritative colouring is grasped only on the green canal. This means that one single RGB photo is enough to receive a picture of the two-dimensional oxygen distribution. On account of the new pictures the Regensburg scientists received hints for an irregular oxygen distribution in the cells and on the oxygen consumption in certain cell regions.
The indicator globules react within few seconds to changes of the local oxygen concentration, so that they can be used in future increasingly to the determination of the cellulose change and the cell respiration. Besides, the research currently assumes that cancer cells can be distinguished with the help of her oxygen consumption from healthy cells. Now with the new sensor technology it is possible to check this supposition experimentally.
The results of the Regensburg scientists have recently appeared in the famous technical periodical "Chemical Science" of the British royal Society of Chemistry (DOI: 10.1039 / C0SC00610F).
For more information please contact Dr. Hans-Heiner Gorri at the University of Regensburg, Institute of analytic chemistry, Chemo-and Biosensorik.