Introduction: Fracture healing involves a complex sequence of physiological events, each of which has important roles in the repair process. Among these, adequate blood supply is the most critical step for bone formation, and disturbed angiogenesis often causes nonunion. In vitro cell-cell interaction studies routinely are executed in transwell systems. However, the static condition does not reflect the dynamic situation in vivo .

Objective: Develop a microfluidic device that provides a dynamic and physiologically relevant context and the mechanism between angiogenesis and osteogenesis.

Methods: We generated molds for an upper and a lower microfluidic channel through 3D printing technology. Casting of the molds was done using Polydimethylsiloxane (PDMS). A porous polycarbonate membrane was inserted before assembly. Finally, the two channel layers were bonded together under air plasma treatment.

For the cellular studies, we cultured mesenchymal stem cells (MSCs) and endothelial cells (ECs) in the device and detected cell viability by live and dead assay and monitored cell movement by fluorescent cell tracker.

Results: The microfluidic device we created was firstly tested by varying rates. Fibronectin coating was used to create a matrix that allows the physiologic way. Our first preliminary experiments indicate that MSCs attach and proliferate well under continuous flow for at least 5 days. Cells showed a healthy morphology with no signs of cytotoxicity.

Conclusion: We developed a microfluidic device to study the crosstalk between angiogenesis and osteogenesis.