Evaluation of an In Vitro Human Dermal Sensitization Test for Use with Medical Device Extracts

Kelly P. Coleman, Lori R. McNamara, Thomas P. Grailer, Jamin A. Willoughby, Sr., Donald J. Keller, Prakash Patel, Simon Thomas, and Clive Dilworth

In accordance with ISO 10993-10, the guinea pig maximization test, Buehler test, or murine local lymph node assay are used to assess the dermal sensitization potential of medical devices. The goal of our study was to determine if the in vitro SenCeeTox assay could be an acceptable alternative. The SenCeeTox assay has previously been shown to accurately predict sensitization by monitoring viability, reactivity, and specific genes known to be crucial in dermal sensitization. Here, 10 known sensitizers were evaluated. Six were incorporated into medical device silicone (10% final concentration) and extracted in polar (physiological saline) and nonpolar (sesame oil) solvents in accordance with ISO 10993-12:2012. The four remaining compounds were added to extracts of plain silicone. This resulted in 20 test solutions (10 compounds in both saline and sesame
oil). The assay controls were prepared directly in saline and sesame oil before exposure. EpiDerm tissues were exposed for 24 hours and tissue viability was assessed by LDH release. Expression of multiple genes controlled by Nrf2/ARE was assessed by qRT-PCR. The test solutions were also assessed for reactivity with glutathione. Eight of the 10 test samples (80%) were correctly identified as negative (nonsensitizers or weak sensitizers) or positive (moderate/strong/extreme sensitizers) in at least one of the two extracts, and 40% of the potencies were correctly identified. Our results indicate that the SenCeeTox assay combined with EpiDerm tissues can detect the presence of sensitizers in medical device extracts. If these findings are confirmed by further studies, then this model may be a suitable replacement for the animal methods currently used to evaluate medical device biocompatibility.


EpiDerm (EPI-296), biomedical devices, biocompatibility, sensitization, SenCeeTox assay, guinea pig maximization test, local lymph node assay (LLNA), Nrf2/ARE, LDH release, polymer extracts

Materials Tested

benzoquinone, Dinitrochlorobenzene (DNCB), phthallic anhydride, chromium acetate, propyl gallate, mercaptobenzothiazol, nickel sulfate, phenyl propanedione, diethyl maleate, phenyl benzoate, benzoquinone, benzoic acid, sesame oil, silicone medical adhesive, polymer extracts, biomedical devices

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