Dynamic Observation of Retinal Response to Pressure Elevation in a Microfluidic Chamber

Dynamic observation of cell and tissue responses to elevated pressure could help our understanding of important physiological and pathological processes related to pressure-induced injury. Here, we report on a microfluidic platform capable of maintaining a wide range of stable operating pressures (30 to 200 mmHg) while using a low flowrate (2-14 μL/h) to limit shear stress. This is achieved by forcing flow through a porous resistance matrix composed of agarose gel downstream of a microfluidic chamber. The flow characteristics were investigated and the permeabilities of the agarose with four different concentrations were extracted, agreeing well with results found in the literature. To demonstrate the capability of the device, we measured the change in intracellular Ca²⁺ levels of retinal ganglion cells in whole mouse retina in response to pressure. The onset of enhanced pressure results in, on average, an immediate 119.16% increase in the intracellular Ca²⁺ levels of retinal ganglion cells. The demonstrated microfluidic platform could be widely used to probe cell and tissue responses to elevated pressure.