A sensing apparatus for sensing target materials including biological or chemical molecules in a fluid. One such apparatus includes a semiconductor-on-insulator (SOI) structure having an electrically-insulating layer, a fluidic channel supported by the SOI structure and configured and arranged to receive and pass a fluid including the target materials, and a semiconductor device including at least three electrically-contiguous semiconductor regions doped to exhibit a common polarity. The semiconductor regions include a sandwiched region sandwiched between two of the other semiconductor regions, and configured and arranged adjacent to the fluidic channel with a surface directed toward the fluidic channel for coupling to the target materials in the fluidic channel, and further arranged for responding to a bias voltage. The sensing apparatus also includes an amplification circuit in or on the SOI and that is arranged to facilitate sensing of the target material near the fluidic channel.