A multishear microfluidic device for quantitative analysis of calcium dynamics in osteoblasts

Microfluidics is a convenient platform to study the influences of fluid shear stress on calcium dynamics. Fluidic shear stress has been proven to affect bone cell functions and remodelling. We have developed a microfluidic system which can generate four shear flows in one device as a means to study cytosolic calcium concentration ([Ca2+]c) dynamics of osteoblasts. Four shear forces were achieved by having four cell culture chambers with different widths while resistance correction channels compensated for the overall resistance to allow equal flow distribution towards the chambers. Computational simulation of the local shear stress distribution highlighted the preferred section in the cell chamber to measure the calcium dynamics. Osteoblasts showed an [Ca2+]c increment proportional to the intensity of the shear stress from 0.03 to 0.30 Pa. A delay in response was observed with an activation threshold between 0.03 and 0.06 Pa. With computational modelling, our microfluidic device can offer controllable multishear stresses and perform quantitative comparisons of shear stress-induced intensity change of calcium in osteoblasts.

► A new multishear microfluidic device was applied on measurement of calcium dynamics.
► A uniform shear stress region was found by computational simulation.
► Quantitative comparison was performed on [Ca2+]c change under varying shear stresses.
► Osteoblasts showed calcium increase proportional to shear stress intensity.
► A response delay was observed with an activation threshold between 0.03 and 0.06 Pa.