Structure and assembly of fluidic sensor devices are disclosed. A fluid sensor in some possible embodiments comprises a unitary/monolithic base body structure, or a base body structure assembled from two or more separate body elements configured to attach one to the other, and the base body structure having a fluid channel passing along the base body structure, an opening formed in said base body structure and fluidly communicating with the channel, and a sealing element comprising one or more sensing elements patterned thereon and sealably attached over the at least one opening such that its one or more sensing elements become located over the at least one opening.