DIN EN ISO 10993-5:2009
This test is used to assess cytotoxicity for medical devices which have contact with human skin. L929 fibroblasts are exposed to different concentrations (e.g. 10%, 30%, 50%, 70% and 100%) of an extract of a medical device for 24 hours. After exposure, fibroblast morphology is evaluated (Prediction 1) and viability is assessed using the MTT test (colorimetric assay). If remaining viability is >70% the medical device is not cytotoxic (Prediction 2).
Prediction Model 1
|discrete intracytoplasmic granule; no cellular dissolution; no inhibition of growth||none||0|
|not more than 20% of cells are round, loosely attached and without any intracytoplasmic granule or show changes in morphology; a few dissolved cells are present, only slight growth inhibition is noticeable||slight||1|
|not more than 50% of cells are round; free of intracytoplasmic granule; no extensive cell dissolution is detected; not more than 50% growth inhibition noticeable||mild||2|
|not more than 70% of cell layers contain round or dissolute cells; layers are not completely destroyed, but more than 50% growth inhibition is noticeable||moderate||3|
|almost complete or complete destruction of cell layers||severe||4|
Prediction Model 2
|Percentage of cell viability||Prediction|
|100 – 70%||Not cytotoxic|
|70 – 50%||Weakly cytotoxic|
|50 – 30%||Moderately cytotoxic|
|30 – 0%||Severely cytotoxic|
If viability is reduced to < 70% of the blank, the test item has cytotoxic potential.