Graphene Field‐Effect Transistors for the Sensitive and Selective Detection of Escherichia coli Using Pyrene‐Tagged DNA Aptamer

Abstract

This study reports biosensing using graphene field-effect transistors with the aid of pyrene-tagged DNA aptamers, which exhibit excellent selectivity, affinity, and stability for Escherichia coli (E. coli) detection. The aptamer is employed as the sensing probe due to its advantages such as high stability and high affinity toward small molecules and even whole cells. The change of the carrier density in the probe-modified graphene due to the attachment of E. coli is discussed theoretically for the first time and also verified experimentally. The conformational change of the aptamer due to the binding of E. coli brings the negatively charged E. coli close to the graphene surface, increasing the hole carrier density efficiently in graphene and achieving electrical detection. The binding of negatively charged E. coli induces holes in graphene, which are pumped into the graphene channel from the contact electrodes. The carrier mobility, which correlates the gate voltage to the electrical signal of the APG-FETs, is analyzed and optimized here. The excellent sensing performance such as low detection limit, high sensitivity, outstanding selectivity and stability of the graphene biosensor for E. coli detection paves the way to develop graphene biosensors for bacterial detection.

Dielectrophoresis assisted rapid, selective and single cell detection of antibiotic resistant bacteria with G-FETs

“…Value of CLG was taken to be 1.65 µF/cm 2 based on the sum of the quantum capacitance (CQ) of graphene and electric double layer capacitance (CDL) consistent with 0.01x PBS. 18 Results from a high mobility device are shown in Figure 1b, while the average hole and electron mobility values obtained from different devices are ~670 ± 125 and ~690 ± 83 cm 2 /V·s, respectively. These mobilities are consistent with reported values for CVD graphene on SiO2 substrates.…”

“…12-15 However, the use of G-FET sensors for bacterial detection is still in its infancy with only a small number of papers describing the detection of a lab strain of Escherichia coli, but no reports on the sensing of clinically relevant pathogenic bacteria, nor on antibiotic resistant strains. [16][17][18]…”

“…This results from the fixed amount of charge per cell, whereas the shift is dependent on the induced charge density. 18 As such the effect of the bacteria on a single G-FET could be enhanced with smaller active areas, however this also requires a far higher cell density, potentially at a level that is much above what is considered to be clinically relevant.…”

Integration of Biomaterials into Sensors Based on Organic Thin‐Film Transistors

“…More importantly, the devices showed no obvious change of output performance when bent at two totally different directions, as seen in Figure c, further demonstrating its potential in flexible and disposable bioelectronics. Recently, Escherichia coli ( E. coli ) was successfully detected using an inorganic graphene‐based FET functionalized with pyrene‐tagged DNA aptamers . The excellent bacterial sensing performance in terms of high sensitivity, selectivity, and stability and low LOD can be ascribed to the effective E. coli ‐induced electrostatic gating via probe–target interaction.…”

Self‐Assembly of Microparticles by Supramolecular Homopolymerization of One Component DNA Molecule

“…One potential application of the self‐assembled DNAµPs was to capture/sequester biologically interesting molecules, for example, microRNAs by hybridization and small molecules by aptamers . To demonstrate the feasibility of such capturing/sequestering, we used the DNAµPs assembled from 4Pt, 5Pt, 6Pt, or 7Pt to sequester a target DNA strand T, which is complementary to the tail of the polymerizable DNAs ( Figure ).…”