Electrostatic melting in a single-molecule field-effect transistor with applications in genomic identification

Abstract

The study of biomolecular interactions at the single-molecule level holds great potential for both basic science and biotechnology applications. Single-molecule studies often rely on fluorescence-based reporting, with signal levels limited by photon emission from single optical reporters. The point-functionalized carbon nanotube transistor, known as the single-molecule field-effect transistor, is a bioelectronics alternative based on intrinsic molecular charge that offers significantly higher signal levels for detection. Such devices are effective for characterizing DNA hybridization kinetics and thermodynamics and enabling emerging applications in genomic identification. In this work, we show that hybridization kinetics can be directly controlled by electrostatic bias applied between the device and the surrounding electrolyte. We perform the first single-molecule experiments demonstrating the use of electrostatics to control molecular binding. Using bias as a proxy for temperature, we demonstrate the feasibility of detecting various concentrations of 20-nt target sequences from the Ebolavirus nucleoprotein gene in a constant-temperature environment.

Electrically Controllable Single-Point Covalent Functionalization of Spin-Cast Carbon-Nanotube Field-Effect Transistor Arrays

“…13,14 Systems employing smFETs transduce high-rate random telegraph signal (RTS) fluctuations directly with bandwidths in excess of 1 MHz over a virtually unlimited observation time. 15 Single-molecule experiments with smFETs have included studies of the dynamics of DNA hybridization, 5 G-quadruplex conformation changes, 16 and lysozyme activity, 17 and these findings harmonize with results from fluorescence-based and force-based experiments. In contrast with these other approaches, the smFET provides for a label-free, low-cost, and scalable miniaturized platform.…”

“…RTS is observed with two discrete conductance levels (high and low) which correspond to the hybridized and melted state of the probe molecule, respectively. 5…”

Molecules under external electric field: On the changes in the electronic structure and validity limits of the theoretical predictions

“…The pursuit of overcoming the associated difficulties has led to the discovery of a variety of novel effects, opening up a myriad of new application possibilities. Single‐molecule transistors, molecular switches and molecular spintronics are examples of such applications that have been extensively explored over last years. In the center of each aforementioned application there is a molecule under external electric field.…”

The Emergence of Insect Odorant Receptor-Based Biosensors

“…Finally, CNT-FET devices are attractive since they are manufactured using traditional microelectronic fabrication techniques [97]. The feasibility of CNT-FET biosensors was demonstrated in the detection of nucleic acids [98][99][100][101] and various protein biomarkers [102] and they are considered the next generation bioelectronic-based biosensors. Detection of VOCs with CNT-FET devices that were bio-functionalized with ORs for specificity is less common [48].…”

“…The rather slow VOC dissolution kinetics may pose an obvious limitation on the sensitivity of such sensors. It should be noted that certain types of bioelectronic sensors, such as CNT-FET, have shown the feasibility of detecting single charges and should, therefore, be capable of detecting low concentrations of solubilized VOCs [100]. Issues of poor solubility and high vapor pressure may additionally be alleviated by modifications of the measurement matrix.…”