Limits...
Label-free sensing of adenosine based on force variations induced by molecular recognition.

Li J, Li Q, Ciacchi LC, Wei G - Biosensors (Basel) (2015)

Bottom Line: The sensitive force response to molecular recognition provided an adenosine detection limit in the range of 0.1 to 1 nM.The addition of guanosine, cytidine, and uridine had no significant interference with the sensing of adenosine, indicating a strong selectivity of this sensor architecture.In addition, operational parameters that may affect the sensor, such as loading rate and solution ionic strength, were investigated.

View Article: PubMed Central - PubMed

Affiliation: Hybrid Materials Interfaces Group, Faculty of Production Engineering, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany. jinfeng@uni-bremen.de.

ABSTRACT
We demonstrate a simple force-based label-free strategy for the highly sensitive sensing of adenosine. An adenosine ssDNA aptamer was bound onto an atomic force microscopy (AFM) probe by covalent modification, and the molecular-interface adsorption force between the aptamer and a flat graphite surface was measured by single-molecule force spectroscopy (SMFS). In the presence of adenosine, the molecular recognition between adenosine and the aptamer resulted in the formation of a folded, hairpin-like DNA structure and hence caused a variation of the adsorption force at the graphite/water interface. The sensitive force response to molecular recognition provided an adenosine detection limit in the range of 0.1 to 1 nM. The addition of guanosine, cytidine, and uridine had no significant interference with the sensing of adenosine, indicating a strong selectivity of this sensor architecture. In addition, operational parameters that may affect the sensor, such as loading rate and solution ionic strength, were investigated.

Show MeSH

Related in: MedlinePlus

Typical AFM height image and corresponding cross-section analysis of the graphite surface prepared by mechanical exfoliation of an HOPG wafer.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4384084&req=5

biosensors-05-00085-f003: Typical AFM height image and corresponding cross-section analysis of the graphite surface prepared by mechanical exfoliation of an HOPG wafer.

Mentions: Flat graphite surfaces were prepared by mechanical exfoliation of an HOPG wafer with Scotch® tape [25]. Before the force spectroscopy measurements, the flatness of graphite surface was first checked by randomly scanning five different areas (2.5 × 2.5 μm) using a bare AFM probe in AC mode in air. Figure 3 shows a typical AFM height image. From the cross-section analysis, a mean roughness of about 0.21 ± 0.07 nm in the 2.5 μm × 2.5 μm area was found, which is definitely flat enough to perform the SMFS experiments.


Label-free sensing of adenosine based on force variations induced by molecular recognition.

Li J, Li Q, Ciacchi LC, Wei G - Biosensors (Basel) (2015)

Typical AFM height image and corresponding cross-section analysis of the graphite surface prepared by mechanical exfoliation of an HOPG wafer.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384084&req=5

biosensors-05-00085-f003: Typical AFM height image and corresponding cross-section analysis of the graphite surface prepared by mechanical exfoliation of an HOPG wafer.
Mentions: Flat graphite surfaces were prepared by mechanical exfoliation of an HOPG wafer with Scotch® tape [25]. Before the force spectroscopy measurements, the flatness of graphite surface was first checked by randomly scanning five different areas (2.5 × 2.5 μm) using a bare AFM probe in AC mode in air. Figure 3 shows a typical AFM height image. From the cross-section analysis, a mean roughness of about 0.21 ± 0.07 nm in the 2.5 μm × 2.5 μm area was found, which is definitely flat enough to perform the SMFS experiments.

Bottom Line: The sensitive force response to molecular recognition provided an adenosine detection limit in the range of 0.1 to 1 nM.The addition of guanosine, cytidine, and uridine had no significant interference with the sensing of adenosine, indicating a strong selectivity of this sensor architecture.In addition, operational parameters that may affect the sensor, such as loading rate and solution ionic strength, were investigated.

View Article: PubMed Central - PubMed

Affiliation: Hybrid Materials Interfaces Group, Faculty of Production Engineering, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany. jinfeng@uni-bremen.de.

ABSTRACT
We demonstrate a simple force-based label-free strategy for the highly sensitive sensing of adenosine. An adenosine ssDNA aptamer was bound onto an atomic force microscopy (AFM) probe by covalent modification, and the molecular-interface adsorption force between the aptamer and a flat graphite surface was measured by single-molecule force spectroscopy (SMFS). In the presence of adenosine, the molecular recognition between adenosine and the aptamer resulted in the formation of a folded, hairpin-like DNA structure and hence caused a variation of the adsorption force at the graphite/water interface. The sensitive force response to molecular recognition provided an adenosine detection limit in the range of 0.1 to 1 nM. The addition of guanosine, cytidine, and uridine had no significant interference with the sensing of adenosine, indicating a strong selectivity of this sensor architecture. In addition, operational parameters that may affect the sensor, such as loading rate and solution ionic strength, were investigated.

Show MeSH
Related in: MedlinePlus