A silicon-based ultrasonic immunoassay for detection of breast cancer antigens

We report on a silicon-based immunosensor package that has direct application to the diagnostic detection of a breast cancer antigen in the sera of breast cancer patients. We couple the flexural plate wave (FPW) gravimetric sensor with a novel mass-amplifying label that increases sensor signal level (a shift of resonant frequency) from that of previous acoustic immunoassays, in which frequency shifts were due solely to the weight of the immunoglobulins. The use of a gravimetric immunoassay with a mass-amplifying label provides an alternative to radioimmunoassay, eliminating the need for radioactive labels that require costly disposal.