Pathogen Detection Using Magnetoelastic Biosentinels - Biomedical Engineering Systems and Technologies - page 53

up to 7 µ m thick have been obtained using this dual-cathode method. Finally, another gold
layer is deposited on top of the iron-boron film so that the magnetostrictive particles are
completely encased in gold. The resonators are freed from the wafer by lift-off using an
acetone rinse and collected using a magnet. Approximately 40,000 sentinels can be
fabricated on an 8 inch wafer at a cost of approximately $28 USD. Hence the cost of a
single ME sensor is less than 1/1000 of a cent.
ME sentinel
( 100 x 30 x 2 µm)
Fig. 6. SEM micrograph comparing the size of a ME resonator with the Y in “LIBERTY” on a
penny. The resonators are microelectronically fabricated and are smaller than a particle of dust.
The resonators require no on-board power and their cost is less than 1/1000 of a cent each when
fabricated in large numbers.
Fig. 7. The ME resonator fabrication process