Role of systemic T-cells and histopathological aspects after subcutaneous implantation of various carbon nanotubes in mice Original Research Article

We have evaluated the biological responses to four different types of carbon nanotubes (CNTs), by measuring CD4+ and CD8+ T-cells in peripheral blood, and by the histopathological study on tissues surrounding subcutaneously implanted CNTs for up to 3 months. All mice survived, and no large changes in their weights were observed within our experimental period. After 1 week, only single-walled carbon nanotubes (SWNTs) activated major histocompatibility complex (MHC) class I pathway of antigen–antibody response system (higher CD4+/CD8+ value), resulting in the appearance of an edematous aspect. After 2 weeks, significantly high values in CD4+ and CD4+/CD8+ without change in CD8+ signified an activated MHC class II for all samples. It is worth noting that the toxicological response of CNTs was absolutely lower than that of asbestos. As a result, we envisaged that our result (relatively low toxicity of CNTs) will spur the mass-production, as well widespread application of CNTs in the near future.