Microfluidic oxygen gradient assay unveils metabolic shifts in HaCaT cell migration under diabetic conditions.

Migration and scratch assays are helpful tools to investigate wound healing and tissue regeneration processes, especially under disease conditions such as diabetes. However, traditional migration (injury-free) assays and scratch (with injury) assays are limited in their control over cellular environments and provide only simplified read-outs of their results. On the other hand, microfluidic-based cell assays offer a distinct advantage in their integration and scalability for multiple modalities and concentrations in a single device. Additionally, in situ stimulation and detection helps to avoid variabilities between individual bioassays. To realize an enhanced, smarter migration assay, we leveraged our multilayered oxygen gradient (1%-16%) to study HaCaT migrations in diabetic conditions with spatial and metabolic read-outs. An analysis of spatial migration over time revealed a new dynamic between hypoxia (at 4.2%-9.1% O2) and hyperglycemia. Furthermore, in situ adenosine triphosphate (ATP) and reactive oxygen species (ROS) responses suggest that this dynamic represents a switch between stationary versus motile modes of metabolism. Thus, low glucose and hypoxia have synergistic effects promoting the migration of cells. These findings illustrate the benefits of spatial microfluidics for modeling complex diseases such as hypoxia and diabetes, where multimodal measurements provide a more deterministic view of the underlying processes.