Eye irritation testing of nanomaterials using the EpiOcular™ eye irritation test and the bovine corneal opacity and permeability assay

Abstract

BackgroundAssessment of eye irritation hazard has long been a core requirement in any chemical legislation. Nevertheless, publications focussing on the eye damaging potential of nanomaterials are scarce. Traditionally, eye irritation testing was performed using rabbits. The OECD Test Guideline 437 Bovine Corneal Opacity and Permeability (BCOP) test method allows determining severely irritating substances without animals, and the recently adopted OECD Test Guideline 492 Reconstructed human cornea-like epithelium test method allows identifying chemicals that neither induce eye irritation nor serious eye damage. For substances applicable to these tests, huge progress has been made in replacing animal testing.MethodsThe in vitro eye irritation potential of 20 nanosized and 3 non-nanosized materials was investigated in a 2-tier EpiOcular™ Eye Irritation Test (EpiOcular™-EIT) and BCOP testing strategy including histopathology of the bovine corneas. Furthermore, applicability of the testing strategy for nanomaterials was assessed. Test materials encompassed OECD representative nanomaterials (metals (Ag), metal oxides (ZnO, TiO2, CeO2), amorphous SiO2 and MWCNTs), three organic pigments, quartz, and talc.ResultsNone of the dry-powder nanomaterials elicited eye irritation in either the EpiOcular™-EIT or the BCOP assay. Likewise, an amorphous SiO2 nanomaterial that was supplied as suspension was tested negative in both assays. By contrast, in the EpiOcular™-EIT, the silver nanomaterial that was supplied as dispersion was tested positive, whereas its surfactant-containing dispersant was borderline to negative. In the BCOP assay, the silver nanomaterial elicited highly variable results and dark-brown patches remained on the corneal surface, whereas the results for its dispersant alone were borderline to positive, which was assessed as inconclusive due to high inter-assay variability.ConclusionThe present study points to the low eye irritation potential of a spectrum of nanomaterials, which is consistent with available in vivo data for the same test materials or for nanosized or bulk materials of the same composition.Electronic supplementary materialThe online version of this article (doi:10.1186/s12989-016-0128-6) contains supplementary material, which is available to authorized users.

In Vitro and In Vivo Short-Term Pulmonary Toxicity of Differently Sized Colloidal Amorphous SiO2

“…Buesen et al [ 92 ] did not record any treatment-related adverse effects of 15 nm SiO 2 (without or with different surface functionalizations) in rats upon 28-day oral administration (OECD TG 407). Hofmann et al [ 93 ] and Wolterbeek et al [ 94 ] observed no reproductive or developmental toxicity of precipitated SiO 2 in rats (OECD TG 414 and 416, respectively); and Kolle et al [ 95 ] reported no in vitro eye-irritating potential of either precipitated or pyrogenic SiO 2 in the bovine corneal opacity and permeability assay (OECD TG 437) or the reconstructed human cornea–like epithelium test method (OECD TG 492).…”

Current characterization methods for cellulose nanomaterials

“…513 For the in situ tests, solid test materials are generally diluted in deionized water prior to application; CNMs will likely agglomerate, resulting in sedimentation and increased concentration directly on the eye. 514 Therefore, applying the dry powdered CNMs directly to the eye might better mimic a realistic situation. Validated tests based on cytotoxicity or cell-function (e.g., the Cytosensor Microphysiometer Test Method and the Fluorescein Leakage Method) are not well-suited to CNMs, as they are recommended for water-soluble substances.…”

Biocompatibility and characterization of polyglycerol-based thermoresponsive nanogels designed as novel drug-delivery systems and their intracellular localization in keratinocytes

“…Furthermore, the potential irritancy of tNGs following unintended contact with the eye was assessed using the BCOP assay and RBC test, the effectiveness of which has recently been demonstrated Kolle et al, 2016;Kumar et al, 2014). Our results clearly indicate that tNGs are devoid of irritating potential for the eye, irrespective of the individual thermoresponsive polymer used.…”

“…However, the use of alternative methods is still desirable no single assay being able to correctly predict the full spectrum of the UN GHS categories (Cat 1, serious, irreversible eye damage vs. Cat 2A, 2B reversible eye irritation) and thus, cannot fully replace the in vivo Draize eye irritation test (Lotz et al, 2016). Therefore, the combination of the BCOP assay with other internationally accepted test methods in a tiered testing strategy is suggested to allow the detailed and structured investigation of eye irritation potential that might be implemented in future (Kolle et al, 2016;Scott et al, 2010).…”