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Sensing Reversible Protein-Ligand Interactions with Single-Walled Carbon Nanotube Field-Effect Transistors.

Münzer AM, Seo W, Morgan GJ, Michael ZP, Zhao Y, Melzer K, Scarpa G, Star A - J Phys Chem C Nanomater Interfaces (2014)

Bottom Line: We report on the reversible detection of CaptAvidin, a tyrosine modified avidin, with single-walled carbon nanotube (SWNT) field-effect transistors (FETs) noncovalently functionalized with biotin moieties using 1-pyrenebutyric acid as a linker.Binding affinities at different pH values were quantified, and the sensor's response at various ionic strengths was analyzed.Moreover, gold nanoparticle decorated SWNT FETs were functionalized with biotin using 1-pyrenebutyric acid as a linker for the CNT surface and (±)-α-lipoic acid linkers for the gold surface, and reversible CaptAvidin binding is shown, paving the way for potential dual mode measurements with the addition of surface enhanced Raman spectroscopy (SERS).

View Article: PubMed Central - PubMed

Affiliation: Institute for Nanoelectronics, Technische Universität München , Arcisstraße 21, 80333, Munich, Germany.

ABSTRACT
We report on the reversible detection of CaptAvidin, a tyrosine modified avidin, with single-walled carbon nanotube (SWNT) field-effect transistors (FETs) noncovalently functionalized with biotin moieties using 1-pyrenebutyric acid as a linker. Binding affinities at different pH values were quantified, and the sensor's response at various ionic strengths was analyzed. Furthermore, protein "fingerprints" of NeutrAvidin and streptavidin were obtained by monitoring their adsorption at several pH values. Moreover, gold nanoparticle decorated SWNT FETs were functionalized with biotin using 1-pyrenebutyric acid as a linker for the CNT surface and (±)-α-lipoic acid linkers for the gold surface, and reversible CaptAvidin binding is shown, paving the way for potential dual mode measurements with the addition of surface enhanced Raman spectroscopy (SERS).

No MeSH data available.


Related in: MedlinePlus

(a) Schematic illustration of an electrolyte-gatedsingle-walledcarbon nanotube field-effect transistor (SWNT FET). (b) Typical transfercurves recorded for the electrical detection of CaptAvidin. Transfercurve 1 was taken before exposure to the protein, 2 after incubationwith 140 nM CaptAvidin, and 3 after 15 min exposure to pH 10 buffer,which is known to reverse the biotin/CaptAvidin binding. (c) Normalizedsensor response (I0–IP)/gm at different bufferpH as a function of CaptAvidin concentration. (d) Effect of Debyescreening length on sensor response to 140 nM CaptAvidin in pH 4 bufferwith varying concentrations of KCl.
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fig1: (a) Schematic illustration of an electrolyte-gatedsingle-walledcarbon nanotube field-effect transistor (SWNT FET). (b) Typical transfercurves recorded for the electrical detection of CaptAvidin. Transfercurve 1 was taken before exposure to the protein, 2 after incubationwith 140 nM CaptAvidin, and 3 after 15 min exposure to pH 10 buffer,which is known to reverse the biotin/CaptAvidin binding. (c) Normalizedsensor response (I0–IP)/gm at different bufferpH as a function of CaptAvidin concentration. (d) Effect of Debyescreening length on sensor response to 140 nM CaptAvidin in pH 4 bufferwith varying concentrations of KCl.

Mentions: SWNT FET deviceswere fabricated as previously reported.14 Briefly, interdigitated electrodes (with channellength of 10 μm) were patterned via a standard photolithographyprocedure on silicon substrates (200 nm SiO2, 30 nm Ti,100 nm Au). P2-SWNTs from Carbon Solutions, Inc. (purity >90%)weredispersed in N,N-dimethylformamide (DMF) and depositedas the active layer between the predefined electrodes via alternatingcurrent dielectrophoresis.15 The chipswere placed onto a ceramic dual in-line package fitted with a liquidcompartment affixed by polydimethylsiloxane (PDMS). Electrical characterizationin this work was conducted by recording transfer curves at a fixedsource-drain bias of 50 mV and sweeping the gate potential from −0.6V to +0.6 V. The transistors were operated in electrolyte-gate modewith a Ag/AgCl electrode immersed in the buffer solution (Figure 1a). All electrical measurements were conducted usingtwo Keithley 2400 sourcemeters.


Sensing Reversible Protein-Ligand Interactions with Single-Walled Carbon Nanotube Field-Effect Transistors.

Münzer AM, Seo W, Morgan GJ, Michael ZP, Zhao Y, Melzer K, Scarpa G, Star A - J Phys Chem C Nanomater Interfaces (2014)

(a) Schematic illustration of an electrolyte-gatedsingle-walledcarbon nanotube field-effect transistor (SWNT FET). (b) Typical transfercurves recorded for the electrical detection of CaptAvidin. Transfercurve 1 was taken before exposure to the protein, 2 after incubationwith 140 nM CaptAvidin, and 3 after 15 min exposure to pH 10 buffer,which is known to reverse the biotin/CaptAvidin binding. (c) Normalizedsensor response (I0–IP)/gm at different bufferpH as a function of CaptAvidin concentration. (d) Effect of Debyescreening length on sensor response to 140 nM CaptAvidin in pH 4 bufferwith varying concentrations of KCl.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126736&req=5

fig1: (a) Schematic illustration of an electrolyte-gatedsingle-walledcarbon nanotube field-effect transistor (SWNT FET). (b) Typical transfercurves recorded for the electrical detection of CaptAvidin. Transfercurve 1 was taken before exposure to the protein, 2 after incubationwith 140 nM CaptAvidin, and 3 after 15 min exposure to pH 10 buffer,which is known to reverse the biotin/CaptAvidin binding. (c) Normalizedsensor response (I0–IP)/gm at different bufferpH as a function of CaptAvidin concentration. (d) Effect of Debyescreening length on sensor response to 140 nM CaptAvidin in pH 4 bufferwith varying concentrations of KCl.
Mentions: SWNT FET deviceswere fabricated as previously reported.14 Briefly, interdigitated electrodes (with channellength of 10 μm) were patterned via a standard photolithographyprocedure on silicon substrates (200 nm SiO2, 30 nm Ti,100 nm Au). P2-SWNTs from Carbon Solutions, Inc. (purity >90%)weredispersed in N,N-dimethylformamide (DMF) and depositedas the active layer between the predefined electrodes via alternatingcurrent dielectrophoresis.15 The chipswere placed onto a ceramic dual in-line package fitted with a liquidcompartment affixed by polydimethylsiloxane (PDMS). Electrical characterizationin this work was conducted by recording transfer curves at a fixedsource-drain bias of 50 mV and sweeping the gate potential from −0.6V to +0.6 V. The transistors were operated in electrolyte-gate modewith a Ag/AgCl electrode immersed in the buffer solution (Figure 1a). All electrical measurements were conducted usingtwo Keithley 2400 sourcemeters.

Bottom Line: We report on the reversible detection of CaptAvidin, a tyrosine modified avidin, with single-walled carbon nanotube (SWNT) field-effect transistors (FETs) noncovalently functionalized with biotin moieties using 1-pyrenebutyric acid as a linker.Binding affinities at different pH values were quantified, and the sensor's response at various ionic strengths was analyzed.Moreover, gold nanoparticle decorated SWNT FETs were functionalized with biotin using 1-pyrenebutyric acid as a linker for the CNT surface and (±)-α-lipoic acid linkers for the gold surface, and reversible CaptAvidin binding is shown, paving the way for potential dual mode measurements with the addition of surface enhanced Raman spectroscopy (SERS).

View Article: PubMed Central - PubMed

Affiliation: Institute for Nanoelectronics, Technische Universität München , Arcisstraße 21, 80333, Munich, Germany.

ABSTRACT
We report on the reversible detection of CaptAvidin, a tyrosine modified avidin, with single-walled carbon nanotube (SWNT) field-effect transistors (FETs) noncovalently functionalized with biotin moieties using 1-pyrenebutyric acid as a linker. Binding affinities at different pH values were quantified, and the sensor's response at various ionic strengths was analyzed. Furthermore, protein "fingerprints" of NeutrAvidin and streptavidin were obtained by monitoring their adsorption at several pH values. Moreover, gold nanoparticle decorated SWNT FETs were functionalized with biotin using 1-pyrenebutyric acid as a linker for the CNT surface and (±)-α-lipoic acid linkers for the gold surface, and reversible CaptAvidin binding is shown, paving the way for potential dual mode measurements with the addition of surface enhanced Raman spectroscopy (SERS).

No MeSH data available.


Related in: MedlinePlus