Patent ID: 6787331
Filing Date: 2004-09-07
Classification: C12M,G01N,Y10S

Abstract:
A process for examining membrane enclosed biocompartments (1), wherein the biocompartments (1) are arranged in a micro-flow chamber (2) which includes an o rational electrode 19 for placing the biocompartments (1) in proximity thereto and a reference electrode (20) separated from the operational electrode (19); the micro-flow chamber (2) is subject to through-flow of a culture medium containing an agent which can affect the biocompartments (1), the medium being in contact with the biocompartments (1) whereby a concentration of a substance is released by and/or consumed by metabolic action into and/or from a portion of a culture medium contained in an activity area of the biocompartment (1), and wherein the pH value of that portion of the culture medium which is found within the micro-flow chamber (2) is measured to determine a metabolic activity of the biocompartment, the process comprising:a) applying a voltage to the culture medium (1) so that hydroxyl ions or hydrogen ions are formed from the substance in the culture medium; b) at a measuring location in the portion of the culture medium, prior to or during the application of the voltage, measuring at least a first measurement value (pHâˆ’1, PHâˆ’3 or pH+1 , pH+3) for a pH value of the culture medium; c) subsequently switching off or changing the voltage so that the formation of hydroxyl and hydrogen ions from the substance is stopped; d) before or after measurement of the first measurement value, (pHâˆ’1, pHâˆ’3 or pH+1, pH+3), upon switching off or changing the voltage such that the formation of hydroxyl and hydrogen ions from the substance is repressed, taking at least one second measurement value (pHâˆ’2, pHâˆ’4 or pH+2, pH30 4) for the pH value of the culture medium; e) calculating a difference between the first measurement value (pHâˆ’1, pHâˆ’3 or pH+1, pH+3) and the second measurement value (pHâˆ’2, pHâˆ’4 or pH+2, pH+4), to produce a measurement value difference (&Dgr;pHâˆ’21, &Dgr;pHâˆ’43 or &Dgr;pHâˆ’21, &Dgr;pHâˆ’43); f) repeating the steps a) to e) at least once; g) calculating a difference between at least two of the meaeu*ed measurement value differences (&Dgr;pHâˆ’21, &Dgr;pHâˆ’43 or &Dgr;pH+21, &Dgr;pH+43) to determine a concentration change of the substance in the culture medium; and calculating a difference between at least two of the first measurement pH values (pHâˆ’1, pHâˆ’3 or pH+1, p+3) and/or calculating a difference between at least two of the second measurement values (pHâˆ’2, pHâˆ’4 or pH+2, pH+4) to determine the an acidification or alkalinization of the culture medium; and h) from the measurement values for the concentration change and the acidification or the alkalinization, determining the metabolic activity of the biocompartments (1).