Surface acoustic wave based biosensor in CMOS for cancer biomarker detection

This paper reports a novel SAW based biosensor developed in CMOS technology for detecting cancer biomarkers in a dip and dry test fashion. The results obtained in our previous work demonstrate that it is possible to design and fabricate SAW delay lines in CMOS with comparable performance to conventional devices. CMOS-SAW devices employ design novelties such as embedded heaters for temperature stability analysis, acoustic absorbers, and EM feedthrough contacts. Due to its highly useful material properties gold was employed as the interface material between the SAW transducers and the selective sensing material of interest, namely streptavidin-biotinylated mammoglobin (hMAM) antibody. A five layered sensing assay was characterized and optimized. The sensitivities of the devices were analyzed primarily based on center frequency shifts. A frequency sensitivity of 8.704 pg/Hz and a mass sensitivity of 2810.25 m²/kg were obtained. Experimental results indicate that it is possible to attach cancer biomarkers to functionalized CMOS-SAW sensor surfaces and selectively detect hMAM antigens with improved sensitivities, lowered costs, and increased reusability.