On pre-cultured cells before the product(s) to be tested are applied:
Constant measurement of the evaporating water which is typical for the wells when coming out of the incubator until a normal TEWL value (for incubated cell cultures) is reached. When the probe starts to measure, the TEWL is very high but constantly decreasing. As soon as it has reached a stable plateau, it indicates that the cell cultures are now ready for the application of the product. At the same time, the recorded TEWL is a control value (before application).
- The probe can constantly measure over longer periods (only possible with open chamber measurements).
- The measurement shows that all cell cultures are ok (quality check).
- The software can indicate that the TEWL has reached a stable threshold value.
- You can be sure to apply the tested products in repeated tests to cell cultures under the same conditions.
- Control value of all wells used is recorded before application, so that the later measured effects can be surely attributed to the product.
Measuring the actual effect of the barrier function of applied products (safety & efficacy):
When the well-plate comes out of the incubator, the TEWL measurement can again be used to monitor when the surplus humidity from the incubator has left the samples and the real measurement time starts. Depending on the nature of the applied products the barrier of the cultured cells is more or less intact. When the barrier has been damaged, particles of the cells can be found (microbiologically) in the surrounding medium. However, the degree of damage or barrier improvement can very accurately be indicated by the monitored TEWL- values. The higher they stay, the less intact the barrier.
- The micro climate in the wells, once they are out of the incubator, is constantly changing. After leaving the incubator, the cultured cells also dry quickly and shrink soon. Therefore, to get meaningful results, it is important to measure all wells at the same time/same conditions and not miss the correct measurement point. If you perform single measurements in each well one after the other, the values will never be comparable. For 24 wells such a procedure would take way too long to get reproducible results.
- Extremely time- (and manpower-) saving and economic.
- The open chamber TEWL measurement do not inhibit the normal evaporation rate and does not cause occlusion.