It is described a hydrogel based transducer device for detecting an environmental state, in particular for detecting an environmental state within a biological material. The transducer device (300) comprises a base element (302), a radiation source (305), which is formed at the base element (302) and which is adapted to emit electromagnetic radiation (306), an optical element (325), which is arranged at the base element (302) and which is adapted to interact with the electromagnetic radiation (306). The transducer device (300) further comprises a radiation detector (350), which is adapted to receive the electromagnetic radiation (326) having interacted with the optical element (325), and a hydrogel material (340), which is mechanically coupled to the optical element (325) and which is adapted to change its volume when getting into contact with an environmental material of the transducer device (300) such that the spatial position of the optical element (325) is changed. The base element (302), the radiation source (305) and the radiation detector (350) are formed integrally from an electronic substrate material.