ISO 10993-10 requires dermal sensitisation assessment using the guinea pig maximisation test (GMPT) for medical device biocompatibility, but it is time consuming and expensive. At the SOT conference in March 2015, Cyprotex and Medtronic jointly presented data on testing of medical device extracts in the SenCeeTox® assay for assessment of skin sensitisation.
Plain and impregnated samples of medical device silicone were extracted following the ISO 10993-12 guidelines in saline (polar) and sesame oil (non-polar) for 72 hours. Some compounds were also prepared directly in the saline and sesame oil. Cultured EpiDerm™ 3D skin tissues were exposed to the solutions. Tissues were rinsed and analysed following a 24 hour exposure period.
The following endpoints were measured:
- LDH release was used to determine tissue viability.
- Direct reactivity was assessed by measuring GSH depletion.
- qRT-PCR analysis was conducted by isolating RNA from EpiDerm™ tissues. Eleven genes involved with Nrf2/ARE pathways were assessed, as were four housekeeping genes.
By combining MatTek’s 3D EpiDerm™ tissues and the SenCeeTox® assay, Medtronic and Cyprotex were able to develop an in vitro assay for skin sensitisation that accurately identified sensitisers and non-sensitisers with 80% accuracy.