Controlling Incoming Macrophages to Implants: Responsiveness of Macrophages to Gelatin Micropatterns under M1/M2 Phenotype Defining Biochemical Stimulations

Abstract

Adverse immune reactions to implanted devices can seriously hamper the efficacy of implants. Monocyte derived macrophages play a crucial role in both initiation and resolution of the inflammatory response toward foreign bodies. As the surface microtopography is shown to exert significant effects on cell phenotype, it is hypothesized that the presence of micropatterns on implant/medical device surfaces can attenuate the immune response. To this end, enzymatically crosslinked micropatterned gelatin films of varying groove widths (2, 5, 10, 20, and 40 µm) are tested for their effect on incoming monocyte behavior. In order to distinguish the effect of cytokine microenvironment on pattern presence, monocytes are seeded on micropatterned films in normal culture medium or M1/M2 inducing media and their morphology and cytokine secretions are observed for 6 d. The presence of the patterns induces microenvironment‐specific changes on the secretions of the attached cells and also on their size. IL‐1ß, IL‐4, IL‐12, TNF‐α, and CCL‐18 secretions are significantly affected particularly in M1 induction media by pattern presence. It is demonstrated for the first time that micropatterned surfaces can be used to control the initial attachment and cytokine secretion of incoming macrophages if they are linked with a polarization inducing cytokine microenvironment.