The effects of surface chemistry on the accumulation of extracellular traps on poly(methyl methacrylate) and the implications on other immune cells

Neutrophil extracellular traps (NETs) are a web of nuclear or mitochondrial DNA and proteins released during the innate immune response. There is a need to better understand the influence of polymer surface chemistry on the release of NETs and their influence on macrophage cells. The impact of biomaterial surface chemistry on the release of NETs was evaluated by incubating HL60 neutrophil-like cells with poly(methyl methacrylate) (PMMA) functionalized with carboxylic acid or amine groups. HL60 cells activated with phorbol 12-myristate 13-acetate (PMA) and incubated on the aminated PMMA had significantly increased cell adhesion and overall NETosis at 48 h compared to HL60 incubated on carboxylated PMMA and unfunctionalized PMMA. NETs were successfully isolated from activated HL60 cells and adsorbed onto tissue culture polystyrene. THP1 monocyte-like cells incubated on surfaces pre-treated with NETs, activated and adhered in the absence of PMA and had decreased live/dead and normalized alamarBlue ratios compared to THP1 with PMA. Cell lines provide a homogenous cell population to explore the role of materials and NETosis. Importantly, surface chemistry modulated the overall amount of NETosis due to differences in adhesion and NETs adsorbed to surfaces altered the activation of downstream cells, warranting increased attention to the impact of NETs on host responses to biomaterials. [GRAPHICS] .