The invention relates to a microfluidic device including a chamber having a fluid inlet, a fluid outlet and a sealable port. In some embodiments, the fluid inlet and the fluid outlet may be positioned to direct fluid flowing from the fluid inlet to the fluid outlet through the chamber. Various embodiments may include a sealable port which may be aligned with the chamber to allow material to be placed directly into, or removed from, the chamber from the exterior of the device when the sealable port is open, and to inhibit and/or prevent fluid escaping through the sealable port when the port is sealed.