Simulating Inflammation in a Wound Microenvironment Using a Dermal Wound-on-a-Chip Model

Considerable progress has been made in the field of microfluidics to develop complex systems for modeling human skin and dermal wound healing processes. While microfluidic models have attempted to integrate multiple cell types and/or 3D culture systems, to date they have lacked some elements needed to fully represent dermal wound healing. This paper describes a cost-effective, multicellular microfluidic system that mimics the paracrine component of early inflammation close to normal wound healing. Collagen and Matrigel are tested as materials for coating and adhesion of dermal fibroblasts and human umbilical vein endothelial cells (HUVECs). The wound-on-chip model consists of three interconnecting channels and is able to simulate wound inflammation by adding tumor necrosis factor alpha (TNF-alpha) or by triculturing with macrophages. Both the approaches significantly increase IL-1 beta, IL-6, IL-8 in the supernatant (p < 0.05), and increases in cytokine levels are attenuated by cotreatment with an anti-inflammatory agent, Dexamethasone. Incorporation of M1 and M2 macrophages cocultured with fibroblasts and HUVECs leads to a stimulation of cytokine production as well as vascular structure formation, particularly with M2 macrophages. In summary, this wound-on-chip system can be used to model the paracrine component of the early inflammatory phase of wound healing and has the potential for the screening of anti-inflammatory compounds.