Modulation of Neutrophil Function by Foetal Bovine Serum and Type I Collagen

Immune regulation plays a crucial role during the regeneration process, and it determines the fate of inflammation after tissue injury or infection. Neutrophils serve as the primary immune cells recruited to the site of inflammation, initiating and directing the subsequent inflammatory cascade following implantation. This study investigated the effects of the in vitro standard foetal bovine serum (FBS), either in the culture medium or as a surface coating, as well as type I collagen coating on responses of neutrophils isolated from human peripheral blood using 3D-printed polycaprolactone (PCL) scaffolds. Neutrophil activity was evaluated by assessing metabolic activity and metabolomic profiles, reactive oxygen species (ROS) production, and inflammation-related markers via high throughput proximity extension assay. Type I collagen coating modified the metabolomic profile of neutrophils and MMP-9 release but had minimal effect on ROS generation. In contrast, the presence of FBS in the culture medium significantly influenced neutrophil behavior, leading to significant changes in metabolic activity, cytotoxicity, and the secretion of inflammation-associated molecules, even at concentrations as low as 1% (v/v). These findings highlight the importance of assessing the use of FBS in neutrophil culture models, particularly those isolated from humans, and emphasize the development of alternative platforms for investigating neutrophil–cell interactions in a more physiologically relevant manner.