摘要
Capacitive detection of affinity-bound biomolecules enables rapid and label-free bioassays suitable for point-of-care diagnostic applications. However, direct detection at high ionic strengths is severely limited by the Debye charge-screening effect of the electric double layer on the sensor surface, leading most studies to be performed at diluted ionic strengths. In this study, probe-target deoxyribonucleic acid (DNA) hybridization was successfully measured by modulating the electric field of the interdigitated sensing electrodes to reduce charge screening. The developed 8 × 8 complementary metal-oxide-semiconductor (CMOS) capacitive sensor array exhibited a sensitivity of 150 fF/log10[DNA] measured at 15 MHz from 10 aM to 100 pM with a response time of approximately 400 s. The array also exhibited a pH sensitivity of 354 fF/pH.