A method of fabricating a sensor comprising a nanowire on a support substrate with a first semiconductor layer arranged on the support substrate is disclosed. The method comprises forming a fin structure from the first semiconductor layer, the fin structure comprising at least two supporting portions and a fin portion arranged there between; oxidizing at least the fin portion of the fin structure thereby forming the nanowire being surrounded by a first layer of oxide; and forming an insulating layer above the supporting portions; wherein the supporting portions and the first insulating layer form a microfluidic channel. A nanowire sensor is also disclosed. The nanowire sensor comprises a support substrate, a semiconducting fin structure arranged on the support substrate, the fin structure comprising at least two semiconducting supporting portions and a nanowire arranged there between; and a first insulating layer on a contact surface of the supporting portions; wherein the supporting portions and the first insulating layer form a microfluidic channel.