A fast CEA analyzer prototype for point of care testing

A CEA (carcinoembryonic antigen) concentration analyzer prototype using a pair of two-port FPW (flexural plate-wave) sensors is proposed in this paper. The proposed prototype utilizes a frequency-shift readout method based upon a peak detecting scheme to measure the resonant frequency shift. The frequency-shift readout circuit is integrated on silicon composed of a linear frequency generator, two peak detectors, two registers, and a subtractor. The frequency scanning range is from 0.9 MHz to 22.4 MHz according to the characteristics of the FPW biosensor. The sensitivity of the peak detector is 5 mV. The proposed frequency-shift readout circuit is verified by a PCB-based prototype, where the CEA serum titration is stabilized after 10 minutes and the linearity of the concentration vs. frequency shift is 97.72%.