A. Rodriguez, G. Greening, P. Cole, H. James, M. Leftwich, G. Erf
Keywords: nanotoxicology, nanomaterials, growthing feather, immunology, nanotoxicity, inflammation, immune response, in vivo test tube
Summary:Nanomaterials have a broad range of biomedical applications. We have developed a novel test using avian models as a platform to analyze complex tissue and cellular immune responses to nanomaterials. This test involves injection of nanomaterials, such as graphene-based compounds, into growing feathers. Growing feathers are a minimally invasive test-site and can be considered “in-vivo test tubes.” Growing feathers are then collected which provides the unique opportunity to monitor the local responses to test-materials in single individuals of an outbred population. This avian “in-vivo test tube” system can provide insight into complex immune system activities initiated by the presence of nanomaterials. The growing feather is a column of skin consisting of pulp. Intradermal injection of nanomaterials into the pulp elicits immune activity; therefore, the pulp is an important window into the bioactivities of injected nanomaterials. The regenerative growing feather can be easily sampled post-injection by pulling it from the follicle for ex-vivo analysis. Examples of ex-vivo measurements include histology, immunohistochemistry, cell population phenotyping, gene-expression at RNA and protein level, reactive oxygen-species generation, enzyme activity, and tissue or cell culture assays. Multiple growing feathers can be used in a single animal, yielding high-powered statistics. Benefits of this avian “in-vivo test tube” system include capturing responses taking place in the same individual over time, testing multiple concentrations of nanomaterials, simultaneous testing of multiple nanomaterials in one individual, using outbred and autoimmune disease susceptible populations, reducing the number of research animals needed, and transitioning to more humane testing procedures. As such, this technique closely follows the principles of replacement, reduction, and refinement implemented by Institutional Animal Care and Use Committees.