A method of operating a microfluidic device may include activating a fluid ejection actuator to eject an amount of fluid from a fluid ejection chamber through a nozzle, and activating a pump located within a micro-fluidic channel fluidically coupled to the fluid ejection actuator during a fluid ejection event to create a positive net flow from the pump to the fluid ejection chamber. The fluid ejection event may include a plurality of ejections of fluid from the nozzle.