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AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential.

Moores B, Simons J, Xu S, Leonenko Z - Nanoscale Res Lett (2011)

Bottom Line: We produced SAMs-patterns made of alternating positively charged, negatively charged, and hydrophobic-terminated thiols by an automated AFM-assisted manipulation, or nanografting.We show that these thiol patterns possess only small topographical differences as revealed by AFM, and distinguished differences in surface potential (20-50 mV), revealed by KPFM.The pattern can be helpful in the development of biosensor technologies, specifically for selective binding of biomolecules based on charge and hydrophobicity, and serve as a model for creating surfaces with quantified alternating surface potential distribution.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada. zleonenk@uwaterloo.ca.

ABSTRACT
Thiol self-assembled monolayers (SAMs) are widely used in many nano- and bio-technology applications. We report a new approach to create and characterize a thiol SAMs micropattern with alternating charges on a flat gold-coated substrate using atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). We produced SAMs-patterns made of alternating positively charged, negatively charged, and hydrophobic-terminated thiols by an automated AFM-assisted manipulation, or nanografting. We show that these thiol patterns possess only small topographical differences as revealed by AFM, and distinguished differences in surface potential (20-50 mV), revealed by KPFM. The pattern can be helpful in the development of biosensor technologies, specifically for selective binding of biomolecules based on charge and hydrophobicity, and serve as a model for creating surfaces with quantified alternating surface potential distribution.

No MeSH data available.


Related in: MedlinePlus

AFM and KPFM of CH3/COOH thiol pattern. Nanopattern (a) topography and (b) KPFM produced using CH3 and COOH thiols. (c,d) show cross-sections of the topography and KPFM, respectively.
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Figure 2: AFM and KPFM of CH3/COOH thiol pattern. Nanopattern (a) topography and (b) KPFM produced using CH3 and COOH thiols. (c,d) show cross-sections of the topography and KPFM, respectively.

Mentions: Figure 2a shows AFM topography image of the two-thiols pattern, created by substituting thiol 1 (CH3-terminated thiol) with thiol 2 (COOH-terminated thiol). Topography does not show much contrast as the two thiols do not differ significantly in height. The cross-section plot for topography image shows flat profile, with exception of few impurities. Figure 2b shows a surface potential map, obtained with KPFM and reveals a pronounced difference (20 mV) in surface potential on the border of two thiols (cross-section plot, Figure 2d).


AFM-assisted fabrication of thiol SAM pattern with alternating quantified surface potential.

Moores B, Simons J, Xu S, Leonenko Z - Nanoscale Res Lett (2011)

AFM and KPFM of CH3/COOH thiol pattern. Nanopattern (a) topography and (b) KPFM produced using CH3 and COOH thiols. (c,d) show cross-sections of the topography and KPFM, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211238&req=5

Figure 2: AFM and KPFM of CH3/COOH thiol pattern. Nanopattern (a) topography and (b) KPFM produced using CH3 and COOH thiols. (c,d) show cross-sections of the topography and KPFM, respectively.
Mentions: Figure 2a shows AFM topography image of the two-thiols pattern, created by substituting thiol 1 (CH3-terminated thiol) with thiol 2 (COOH-terminated thiol). Topography does not show much contrast as the two thiols do not differ significantly in height. The cross-section plot for topography image shows flat profile, with exception of few impurities. Figure 2b shows a surface potential map, obtained with KPFM and reveals a pronounced difference (20 mV) in surface potential on the border of two thiols (cross-section plot, Figure 2d).

Bottom Line: We produced SAMs-patterns made of alternating positively charged, negatively charged, and hydrophobic-terminated thiols by an automated AFM-assisted manipulation, or nanografting.We show that these thiol patterns possess only small topographical differences as revealed by AFM, and distinguished differences in surface potential (20-50 mV), revealed by KPFM.The pattern can be helpful in the development of biosensor technologies, specifically for selective binding of biomolecules based on charge and hydrophobicity, and serve as a model for creating surfaces with quantified alternating surface potential distribution.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada. zleonenk@uwaterloo.ca.

ABSTRACT
Thiol self-assembled monolayers (SAMs) are widely used in many nano- and bio-technology applications. We report a new approach to create and characterize a thiol SAMs micropattern with alternating charges on a flat gold-coated substrate using atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). We produced SAMs-patterns made of alternating positively charged, negatively charged, and hydrophobic-terminated thiols by an automated AFM-assisted manipulation, or nanografting. We show that these thiol patterns possess only small topographical differences as revealed by AFM, and distinguished differences in surface potential (20-50 mV), revealed by KPFM. The pattern can be helpful in the development of biosensor technologies, specifically for selective binding of biomolecules based on charge and hydrophobicity, and serve as a model for creating surfaces with quantified alternating surface potential distribution.

No MeSH data available.


Related in: MedlinePlus