Highly Sensitive DNA Detection Beyond the Debye Screening Length Using CMOS Field Effect Transistors

Field effect transistors are considered one of the key technologies to provide real-time and label-free biodetection. Direct detection in physiological solutions is, however, severely limited by the Debye charge-screening effect of the electrical double layer. Most measurements are therefore performed indirectly in diluted ionic-strength solutions. This study proposes a general technique based on modulation of the surface electric field of the CMOS (complementary metal oxide semiconductor) extended-gate field effect transistors (EGFETs) to investigate the screening effect on hybridized DNA (deoxyribonucleic acid) signals from 1 MHz to 15 MHz. The 32 EGFET sensor array exhibited a floating-gate potential change of 17.4 mV/log[DNA] from 1 fM to 100 pM with a near picomolar-level resolution and a response time below 8 minutes.

Automated summary

Field effect transistors are a key technology for real-time and label-free biodetection. This study proposes a technique based on modulating the surface electric field to investigate the charge screening effect on hybridized DNA signals. The results demonstrate high sensitivity and fast response time of the proposed technique.