a biosensor is for sensing analytes in a fluid . the biosensor may include a first structural layer having a first hydrogel , a second structural layer having a second hydrogel , and a bioactive region extending between the first structural layer and the second structural layer and having a third hydrogel . the biosensor may include a first electrode coupled to the bioactive region , and a second electrode coupled to the first structural layer and being spaced apart from the bioactive region . the second structural layer may have a through opening adjacent the bioactive region , and the bioactive region may be configured to be in fluid communication with an environment external to the biosensor for receiving the fluid comprising the analytes .