Methods for detecting the effect of cell affecting agents on living cells

A method for microbial identification comprising:

• (a) providing a micro flow chamber adapted for continuous or intermittent flow of solutions or suspensions through the micro flow chamber wherein a portion of the micro flow chamber is a silicon semiconducting electrode and wherein the micro flow chamber has a means for trapping microbes to be identified on or in the immediate vicinity of the silicon semiconducting electrode;
• (b) sequentially flowing a predetermined set of solutions or suspensions through the micro flow chamber where each solution or suspension contains one or more ingredients that effect the rate of pH change of the microbe being tested when contacted with the microbe to be identified;
• (c) repetitively stopping the flow and repetitively measuring the change in pH when the flow is stopped by means of the silicon semiconducting electrode within about 100 .mu.m of the cells and where the pH change is about 0.1 to 0.5 pH units in about 1 to 4 minutes,
• (d) comparing the measuring microbe response in pH change to the predetermined set of solutions or suspensions to the response of known bacteria thereby identifying the bacteria to be identified.

A method for screening the presence or activity of a drug comprising:

• (a) providing a micro flow chamber with a portion of the micro flow chamber being a silicon semiconductor electrode, said micro flow chamber being adapted for continuous or intermittent flow of solutions or suspensions containing a drug to be tested through the micro flow chamber;
• (b) further providing living cells responsive to the drug in the micro flow chamber in contact with or in the immediate vicinity of the silicon semiconductor electrode;
• (c) contacting the living cells with the drug to be tested by flowing a solution or suspension of the drug to be tested through the micro flow chamber and repetitively stopping the flow;
• and
• (d) repetitively measuring the change in pH when the flow is stopped by means of the silicon semiconductor electrode within about 100 .mu.m from the cells and where the pH changes is about 0.1 to 0.5 pH units in about 1 to 4 minutes.

A method for detecting a toxic substance comprising:

• (a) providing a micro flow chamber wherein a portion of the micro flow chamber is a silicon semiconductor electrode, the micro flow chamber being adapted for continuous or intermittent flow of a solution or suspension suspected of containing a toxic substance;
• (b) further providing living cells responsive to the toxic substance being tested in the micro flow chamber in contact with or in the immediate vicinity of the silicon semiconductor electrode;
• (c) contacting the living cells with the solution or suspension suspected of containing the toxic substance by flowing the solution or suspension through the micro flow chamber and repetitively stopping the flow;
• and
• (d) repetitively measuring the change in pH when the flow is stopped by means of the silicon semiconductor electrode within about 100 .mu.m of the cells and wherein the pH change is about 0.1 to 0.5 pH units in about 1 to 4 minutes.