Nano and microparticles (polystyrene and silica) interactions with the immune system 

June 21st, 2024

Presentation by Dr Kirsty Wilson (RMIT University)

Nanoparticles come in many different shapes, sizes and compositions. This plethora of physicochemical properties affects how nanoparticles interact in biological environments, including with cells of the immune system. Solid polystyrene nanoparticles (PSNPs) in the viral to bacterial size range (40nm-1000nm) are an excellent model to study the impact of solid materials in the nano-micro range, such as plastics, on uptake by immune cells as well as downstream effects on inflammation and the immune system in general. PSNPs in the viral size range (40-100nm) by themselves are rapidly taken up by activating immune cells such as dendritic cells, but surprisingly do not induce conventional inflammatory pathways. By themselves these viral sized PSNPs do not induce immune responses, however robust T and B cell responses are seen when PSNPs are used as a vaccine delivery platform. Larger particles (500-1000nm), by themselves are by contrast taken up preferentially by immune cells such a myeloid derived suppressor cells (MDSC) associated with the induction of immune-suppression. This shows that small changes in the nano to micro scale for the size of solid man-made particles such as PSNPs have significant, unique and potentially divergent effects on the immune system.