Fiber-optic pH detection of small volumes of bio-samples

Year: 2010

Ivan Kašík, Ph.D.

Determination of pH in microscopic bio-samples has been in focus of interest of botanists for years since knowledge of pH values or pH gradients can contribute to explanation of complex processes in animal or plant organisms . In such cases analyzed samples have often small volumes in a range from microliters down to volumes of individual cells with diameters 20-50 µm. Therefore, substantial effort over the world has been expended to develop suitable microsensors for such measurements. In the Institute of Photonics and Electronics AS CR, v.v.i. (IPE), a fiber-optic detection method utilizing novel optical sensing probes was developed and realized. The transversal dimension of the probes was reduced down to several micrometers allowing non-invasive analyses even of small droplets of the volume of the order of a few microlitres. The developed sensing probes were successfully tested and implemented for pH measurements of in vivo and in vitro samples of exudates excreted by leaves of cultivated oat plants of a volume of about 6 microliters. The data obtained from these measurements are essential for research of mass transport in plants including that of water, nutrients and phytohormones. The results were achieved by joint effort of researchers dealing with the fiber-optic technology, sol-gel immobilization techniques and optical detection from IPE and biochemists and biologists from the Institute of Experimental Botany AS CR, v.v.i., colaborating together with other teams in Centre of Excellence LC06034 – Remorost.

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