Osteocyte culture in microfluidic devices.

This paper presents a microfluidic device (poly-dimethylsiloxane micro channels bonded with glass slides) enabling culture of MLO-Y4 osteocyte like cells. In this study, on-chip collagen coating, cell seeding and culture, as well as staining were demonstrated in a tubing-free manner where gravity was used as the driving force for liquid transportation. MLO-Y4 cells were cultured in microfluidic channels with and without collagen coating where cellular images in a time sequence were taken and analyzed, confirming the positive effect of collagen coating on phenotype maintaining of MLO-Y4 cells. The proliferating cell nuclear antigen based proliferation assay was used to study cellular proliferation, revealing a higher proliferation rate of MLO-Y4 cells seeded in microfluidic channels without collagen coating compared to the substrates coated with collagen. Furthermore, the effects of channel dimensions (variations in width and height) on the viability of MLO-Y4 cells were explored based on the Calcein-AM and propidium iodide based live/dead assay and the Hoechst 33258 based apoptosis assay, locating the correlation between the decrease in channel width or height and the decrease in cell viability. As a platform technology, this microfluidic device may function as a new cell culture model enabling studies of osteocytes.