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Selectively Sized Graphene-Based Nanopores for in Situ Single Molecule Sensing.

Crick CR, Sze JY, Rosillo-Lopez M, Salzmann CG, Edel JB - ACS Appl Mater Interfaces (2015)

Bottom Line: The precise tailoring of nanopore size is a significant step toward achieving this, as it would allow for a nanopore to be tuned to a corresponding analyte.The translocation of DNA is studied as the pore size is varied, allowing for subfeatures of DNA to be detected with slower DNA translocations at smaller pore sizes, and the ability to observe trends as the pore is opened.This approach opens the door to creating a device that can be target to detect specific analytes.

View Article: PubMed Central - PubMed

Affiliation: †Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.

ABSTRACT
The use of nanopore biosensors is set to be extremely important in developing precise single molecule detectors and providing highly sensitive advanced analysis of biological molecules. The precise tailoring of nanopore size is a significant step toward achieving this, as it would allow for a nanopore to be tuned to a corresponding analyte. The work presented here details a methodology for selectively opening nanopores in real-time. The tunable nanopores on a quartz nanopipette platform are fabricated using the electroetching of a graphene-based membrane constructed from individual graphene nanoflakes (ø ∼30 nm). The device design allows for in situ opening of the graphene membrane, from fully closed to fully opened (ø ∼25 nm), a feature that has yet to be reported in the literature. The translocation of DNA is studied as the pore size is varied, allowing for subfeatures of DNA to be detected with slower DNA translocations at smaller pore sizes, and the ability to observe trends as the pore is opened. This approach opens the door to creating a device that can be target to detect specific analytes.

No MeSH data available.


Related in: MedlinePlus

Translocationdata for 10 kbp DNA through nanopores treated with multilayered graphenemembrane. (A) Current–time traces of DNA translocations througha GNF coated nanopores. Individual translocation events are also shown.(B) “Half-violin” plots showing the average dwell timeat different size of pore at various stages of opening, the overalltrend shows the dwell time decreases as the pore diameter increases.(C) Translocation data from pipette membranes fabricated using aninitial 1.5 mg mL–1 GNF solution. The data showsthe separation of DNA conformations as the applied potential is varied.All of the applied potentials have translocation events that occurat ∼50 pA, this splits into two populations for both the 300mV (∼75 pA) and 400 mV (∼125 pA) cases. The estimatedpore size for this was ∼22 nm.
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fig4: Translocationdata for 10 kbp DNA through nanopores treated with multilayered graphenemembrane. (A) Current–time traces of DNA translocations througha GNF coated nanopores. Individual translocation events are also shown.(B) “Half-violin” plots showing the average dwell timeat different size of pore at various stages of opening, the overalltrend shows the dwell time decreases as the pore diameter increases.(C) Translocation data from pipette membranes fabricated using aninitial 1.5 mg mL–1 GNF solution. The data showsthe separation of DNA conformations as the applied potential is varied.All of the applied potentials have translocation events that occurat ∼50 pA, this splits into two populations for both the 300mV (∼75 pA) and 400 mV (∼125 pA) cases. The estimatedpore size for this was ∼22 nm.

Mentions: The translocation behavior of DNA was then studied,the aim was to monitor variations in translocation behavior as thegraphene membrane was opened. All of the reported DNA translocationswere carried out using one type of DNA (10 kbp). With full characterizationof the translocation behavior of the DNA carried out on untreatedpipettes. Both the DNA concentration and ionic strength of the solutionwere kept constant throughout all reported experiments, however thepotential applied to drive the translocations was varied. This changein applied potential provides differences in observed translocations(Figure 4). The current–time tracesshow a positive spike in current as the DNA passes through due tothe extra charge carried by the DNA molecule. The features of eachspike is characteristic of the pore properties, in addition to theconformation of the DNA as it passes through the nanopore (Figure 4A). The most important features of these tracesare the dwell time (the total time for a translocation event), peakamplitude (the maximum height of a translocation peak from the baseline)and charge (the integrated area underneath the plotted translocationevent). Detailed analysis of multiple translocation events revealstypical values of 0.37 (±0.02) ms, 59.3 (±3.6) pA, and 17.1(±2.17) fA for dwell time, peak amplitude, and charge, respectively,at an applied potential of 300 mV, using untreated nanopipettes.


Selectively Sized Graphene-Based Nanopores for in Situ Single Molecule Sensing.

Crick CR, Sze JY, Rosillo-Lopez M, Salzmann CG, Edel JB - ACS Appl Mater Interfaces (2015)

Translocationdata for 10 kbp DNA through nanopores treated with multilayered graphenemembrane. (A) Current–time traces of DNA translocations througha GNF coated nanopores. Individual translocation events are also shown.(B) “Half-violin” plots showing the average dwell timeat different size of pore at various stages of opening, the overalltrend shows the dwell time decreases as the pore diameter increases.(C) Translocation data from pipette membranes fabricated using aninitial 1.5 mg mL–1 GNF solution. The data showsthe separation of DNA conformations as the applied potential is varied.All of the applied potentials have translocation events that occurat ∼50 pA, this splits into two populations for both the 300mV (∼75 pA) and 400 mV (∼125 pA) cases. The estimatedpore size for this was ∼22 nm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543996&req=5

fig4: Translocationdata for 10 kbp DNA through nanopores treated with multilayered graphenemembrane. (A) Current–time traces of DNA translocations througha GNF coated nanopores. Individual translocation events are also shown.(B) “Half-violin” plots showing the average dwell timeat different size of pore at various stages of opening, the overalltrend shows the dwell time decreases as the pore diameter increases.(C) Translocation data from pipette membranes fabricated using aninitial 1.5 mg mL–1 GNF solution. The data showsthe separation of DNA conformations as the applied potential is varied.All of the applied potentials have translocation events that occurat ∼50 pA, this splits into two populations for both the 300mV (∼75 pA) and 400 mV (∼125 pA) cases. The estimatedpore size for this was ∼22 nm.
Mentions: The translocation behavior of DNA was then studied,the aim was to monitor variations in translocation behavior as thegraphene membrane was opened. All of the reported DNA translocationswere carried out using one type of DNA (10 kbp). With full characterizationof the translocation behavior of the DNA carried out on untreatedpipettes. Both the DNA concentration and ionic strength of the solutionwere kept constant throughout all reported experiments, however thepotential applied to drive the translocations was varied. This changein applied potential provides differences in observed translocations(Figure 4). The current–time tracesshow a positive spike in current as the DNA passes through due tothe extra charge carried by the DNA molecule. The features of eachspike is characteristic of the pore properties, in addition to theconformation of the DNA as it passes through the nanopore (Figure 4A). The most important features of these tracesare the dwell time (the total time for a translocation event), peakamplitude (the maximum height of a translocation peak from the baseline)and charge (the integrated area underneath the plotted translocationevent). Detailed analysis of multiple translocation events revealstypical values of 0.37 (±0.02) ms, 59.3 (±3.6) pA, and 17.1(±2.17) fA for dwell time, peak amplitude, and charge, respectively,at an applied potential of 300 mV, using untreated nanopipettes.

Bottom Line: The precise tailoring of nanopore size is a significant step toward achieving this, as it would allow for a nanopore to be tuned to a corresponding analyte.The translocation of DNA is studied as the pore size is varied, allowing for subfeatures of DNA to be detected with slower DNA translocations at smaller pore sizes, and the ability to observe trends as the pore is opened.This approach opens the door to creating a device that can be target to detect specific analytes.

View Article: PubMed Central - PubMed

Affiliation: †Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.

ABSTRACT
The use of nanopore biosensors is set to be extremely important in developing precise single molecule detectors and providing highly sensitive advanced analysis of biological molecules. The precise tailoring of nanopore size is a significant step toward achieving this, as it would allow for a nanopore to be tuned to a corresponding analyte. The work presented here details a methodology for selectively opening nanopores in real-time. The tunable nanopores on a quartz nanopipette platform are fabricated using the electroetching of a graphene-based membrane constructed from individual graphene nanoflakes (ø ∼30 nm). The device design allows for in situ opening of the graphene membrane, from fully closed to fully opened (ø ∼25 nm), a feature that has yet to be reported in the literature. The translocation of DNA is studied as the pore size is varied, allowing for subfeatures of DNA to be detected with slower DNA translocations at smaller pore sizes, and the ability to observe trends as the pore is opened. This approach opens the door to creating a device that can be target to detect specific analytes.

No MeSH data available.


Related in: MedlinePlus