A microfluidic device (100) is disclosed. The device comprises a triboelectric sensor (102)； an elastically deformable pump (104) arranged to transfer fluid to at least one fluid outlet (108) and triboelectrically activate the sensor； and first and second check valves (106a, 106b) respectively arranged at the inlet and outlet of the pump to control fluid transfer in and out of the pump. When the pump is actuated in conjunction with the check valves to transfer a volume of fluid, at least a portion of the sensor is triboelectrically activated according to an amount of deformation of the pump to generate a corresponding output voltage signal for enabling the volume of fluid transferred by the deformed pump to be determined. A corresponding method of using the device is also disclosed.
