Applicability of the SENS-IS assay to assess skin sensitization of medical devices according the technical specification ISO/TS11796.

Assessing skin sensitization is critical in the development of medical devices, and the SENS-IS assay provides a reliable in vitro alternative to traditional animal models. By utilizing reconstructed human epidermis (RHE), which closely mimics human skin, the assay allows testing with both saline and sesame oil under conditions similar to in vivo models, facilitating a smoother transition to non-animal testing. This study evaluated the efficacy of the SENS-IS assay according to ISO/TS 11796, testing 14 sensitizers and 3 non-sensitizers during the prevalidation phase, as well as the 8 sensitizers and 4 non-sensitizers recommended in an interlaboratory study using MED-2000 silicone extracts spiked with ISO-specified chemicals at LLNA EC3 concentrations. The assay successfully identified 20 out of 22 sensitizers tested at EC3 concentrations. Two chemicals, poorly soluble in the vehicles used,-TPO (EC3 = 27) and Isopropyl Myristate (EC3 = 44)-were detected at slightly higher concentrations, with TPO detected at 50 % and Isopropyl Myristate at 75 % of their EC3 values. All 7 non-sensitizers were accurately classified. These results confirm the sensitivity of the SENS-IS assay and underscore its potential for medical device development, advancing the use of non-animal testing methods.