Non-invasive, in vitro functional tissue assay systems

1. An in vitro method for screening at least one test substance for an effect on an isolated population of cardiomyocyte cells, comprising:

providing an electrode array comprising one or more isolated populations of cardiomyocyte cells having been obtained by differentiating mouse or human pluripotent stem cells, wherein the stem cells have been genetically altered to comprise a selectable marker operably linked to a regulatory sequence specific for a first cell type, wherein the one or more isolated population of cells have been differentiated and depleted of undifferentiated cells and/or of non-cardiomyocyte cells by using a selection system that is lethal to the undifferentiated cells and/or non-cardiomyocyte cells by expressing a selectable marker gene that renders cells of the first cell type resistant to the lethal effect,

contacting the populations of cardiomyocyte cells in an electrode array with the at least one test substance; and

measuring the electrical activity of the contacted cardiomyocyte cells with the electrode array and analyzing at least one parameter selected from the group consisting of:

(i) Na+ channel activity,

(ii) Ca2+/K+ channel activity,

(iii) K+ channel activity;

(iv) amplitude and/or field potential duration,

(v) chronotropy,

(vi) arrhythmia,

(vii) pH-value,

(viii) oxygen partial pressure,

(ix) beating arrest and/or beating frequency,

(x) contractility,

(xi) analysis of AV-dissociation contractility,

(xii) conductivity and/or impedance,

(xiii) nitrous oxide-effects, or

(xiv) morphological changes; and

selecting a test substance that has an effect on at least one parameter in the measuring step as compared to cardiomyocyte cells of the same type which were not contacted with a test substance and wherein a change in said at least one parameter indicates that the test substance has an effect on the populations of cardiomyocyte cells.

2. The method of claim 1 , wherein said pluripotent stem cells are embryonic stem (ES) cells.

3. The method of claim 1 , wherein the selectable marker confers resistance to puromycin, neomycin, or hygromycin.

4. The method of claim 1 , wherein said electrode array comprises one or more electrodes.

5. The method of claim 1 , wherein said electrode array is a multi- or microelectrode array (MEA).

6. The method of claim 4 , wherein the electrode array is coated with fibronectin.

7. The method of claim 1 , wherein at least one of the parameters analyzed is selected from the group consisting of: beating frequency, mean contractility, maximum contraction, and mean area of contraction.

8. The method of claim 1 , wherein the at least one test substance is one of a collection of test substances.

9. The method of claim 8 , wherein said collection of test substances comprises about 10 3 to about 10 5 substances.

10. The method of claim 1 , wherein three or more measurements are taken.

11. The method of claim 1 , further comprising removing the measured cells.

12. The method of claim 10 , wherein said measurements are taken at different positions within the array.

13. The method of claim 1 , wherein said selection step positively screens a test substance.

14. The method of claim 1 , wherein said selection step screens out a test substance.

15. The method of claim 1 , wherein said selection step determines the toxicity of the test substance on the cells.