Ultrasensitive in Situ Label-Free DNA Detection Using a GaN Nanowire-Based Extended-Gate Field-Effect-Transistor Sensor

Abstract

In this study, we have successfully demonstrated that a GaN nanowire (GaNNW) based extended-gate field-effect-transistor (EGFET) biosensor is capable of specific DNA sequence identification under label-free in situ conditions. Our approach shows excellent integration of the wide bandgap semiconducting nature of GaN, surface-sensitivity of the NW-structure, and high transducing performance of the EGFET-design. The simple sensor-architecture, by direct assembly of as-synthesized GaNNWs with a commercial FET device, can achieve an ultrahigh detection limit below attomolar level concentrations: about 3 orders of magnitude higher in resolution than that of other FET-based DNA-sensors. Comparative in situ studies on mismatches ("hotspot" mutations related to human p53 tumor-suppressor gene) and complementary targets reveal excellent selectivity and specificity of the sensor, even in the presence of noncomplementary DNA strands, suggesting the potential pragmatic application in complex clinical samples. In comparison with GaN thin film, NW-based EGFET exhibits excellent performance with about 2 orders higher sensitivity, over a wide detection range, 10(-19)-10(-6) M, reaching about a 6-orders lower detection limit. Investigations illustrate the unique and distinguished feature of nanomaterials. Detailed studies indicate a positive effect of energy band alignment at the biomaterials-semiconductor hybrid interface influencing the effective capacitance and carrier-mobility of the system.

Mechanisms of Ion Detection for FET-Sensors Using FTO: Role of Cleaning Process, pH Sequence and Electrical Resistivity

“…Interesting works have described the use of EGFET as component of a biosensor to detect, for example, DNA 9,10 , CO 2 11 , O 2 …”

Micro- and nano-structure based oligonucleotide sensors

“…The sensitivity of MEMS and NEMS-based sensors is broadly similar to those of existing electrochemical or optical techniques (Liu et al, 2012;Sassolas et al, 2008); and some groups have reported superior sensitivities Chen et al, 2011). However, with some exceptions, MEMS and NEMSbased oligonucleotide sensors are label-free which renders their sensing mechanisms far simpler than most electrochemical or optical techniques in terms of steps involved and reagents required.…”

“…However, other materials such as gold (Andreu et al, 2006;Fang and Kelley, 2009), gallium nitride (Chen et al, 2011), carbon nanotubes (Sorgenfrei et al, 2011;Star et al, 2006), graphene oxide (Stine et al, 2010) and indium oxide (Tang et al, 2005) have been used. It is also possible to exploit NWs for oligonucleotide sensing in ways other than the FET-based approach that has been described.…”

Silicon-Based Platform for Biosensing Applications

“…For example, Dai and coworkers developed carbon nanotube-based FET for detection of protein or protein-protein interaction in wide-ranging concentrations from 100 pM to 100 nM [13]. Chen et al presented a kind of GaN nanowires based extended-gate FET biosensor capable of specific and sensitive (10 -18 M) DNA sequence identification [27].…”