Label-Free DNA Sensing Platform with Low-Voltage Electrolyte-Gated
Transistors
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Abstract
We
report a method to measure DNA hybridization potentiometrically
in a manner conducive to portable or hand-held biosensors. An electrolyte-gated
transistor (EGT) based on poly(3-hexylthiophene) (P3HT) and an ion-gel
serves as a transducer for surface hybridization of DNA. The key aspect
of the design is the use of a floating-gate electrode functionalized
with ssDNA whose potential is determined by both capacitive coupling
with a primary, addressable gate electrode and the presence of adsorbed
molecules. When DNA is hybridized at the floating gate, it offsets
the primary gate voltage felt by the P3HT semiconductor; the offset
is directly measurable and quantitatively related to the number density
of dsDNA molecules. The presented sensing strategy can be readily
adapted to other biomolecules of interest and integrated into a microfluidic
system for field applications of biosensors