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bOptimizing atomic force microscopy for characterization of diamond-protein interfaces.

Rezek B, Ukraintsev E, Kromka A - Nanoscale Res Lett (2011)

Bottom Line: We show that both diamond and proteins can be mechanically modified by Si AFM cantilever.We propose how to choose suitable cantilever type, optimize scanning parameters, recognize and minimize various artifacts, and obtain reliable AFM data both in solution and in air to reveal microscopic characteristics of protein-diamond interfaces.We also suggest that monocrystalline diamond is well defined substrate that can be applicable for fundamental studies of molecules on surfaces in general.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16253 Prague 6, Czech Republic. ukraints@fzu.cz.

ABSTRACT
Atomic force microscopy (AFM) in contact mode and tapping mode is employed for high resolution studies of soft organic molecules (fetal bovine serum proteins) on hard inorganic diamond substrates in solution and air. Various effects in morphology and phase measurements related to the cantilever spring constant, amplitude of tip oscillations, surface approach, tip shape and condition are demonstrated and discussed based on the proposed schematic models. We show that both diamond and proteins can be mechanically modified by Si AFM cantilever. We propose how to choose suitable cantilever type, optimize scanning parameters, recognize and minimize various artifacts, and obtain reliable AFM data both in solution and in air to reveal microscopic characteristics of protein-diamond interfaces. We also suggest that monocrystalline diamond is well defined substrate that can be applicable for fundamental studies of molecules on surfaces in general.

No MeSH data available.


Related in: MedlinePlus

Wear of diamond substrates in contact mode AFM. (a) Two 2 × 2 μm2 CM scans with F = 3 μN were made in the central area using NSG01 tip with k = 3 N/m. Overall image in TM reveal holes with depth h = 20 ± 15 nm. (b) CM nanoshaving (2 × 2 μm2) image of NCD was made in air using NSG01 tip with applied force F = 1.5 μN. Overall image in TM reveal hole with depth h = 6 ± 12 nm. (c) CM nanoshaving (1 × 1 μm2) on MCD surface was made using NSG01 tip with F = 3 μN (k = 3 N/m). Overall image in TM (2 × 2 μm2) reveals absence of any changes on the surface. (d) The model illustrating wear of NCD grains by Si cantilever. CM nanoshaving makes NCD grains more rounded and their Lx values slightly increases. (e) The model illustrates formation of a depression in the NCD surface by the wear of NCD grains during AFM scanning in CM.
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Figure 3: Wear of diamond substrates in contact mode AFM. (a) Two 2 × 2 μm2 CM scans with F = 3 μN were made in the central area using NSG01 tip with k = 3 N/m. Overall image in TM reveal holes with depth h = 20 ± 15 nm. (b) CM nanoshaving (2 × 2 μm2) image of NCD was made in air using NSG01 tip with applied force F = 1.5 μN. Overall image in TM reveal hole with depth h = 6 ± 12 nm. (c) CM nanoshaving (1 × 1 μm2) on MCD surface was made using NSG01 tip with F = 3 μN (k = 3 N/m). Overall image in TM (2 × 2 μm2) reveals absence of any changes on the surface. (d) The model illustrating wear of NCD grains by Si cantilever. CM nanoshaving makes NCD grains more rounded and their Lx values slightly increases. (e) The model illustrates formation of a depression in the NCD surface by the wear of NCD grains during AFM scanning in CM.

Mentions: Figure 3 shows the effect of AFM scanning on the diamond substrate itself and compares monocrystalline and NCDs in this aspect. Figure 3c shows that even when quite a high force (F = 3 μN) is applied to silicon tip (NSG01, NTM-DT) CM scan does not change the surface of the MCD. Figure 3a shows that similar force can modify the surface of the NCD. Overall image in TM reveals depressions h = 20 ± 15 nm deep. During this process the silicon tip is damaged. This is the reason for square like patterns in the image.


bOptimizing atomic force microscopy for characterization of diamond-protein interfaces.

Rezek B, Ukraintsev E, Kromka A - Nanoscale Res Lett (2011)

Wear of diamond substrates in contact mode AFM. (a) Two 2 × 2 μm2 CM scans with F = 3 μN were made in the central area using NSG01 tip with k = 3 N/m. Overall image in TM reveal holes with depth h = 20 ± 15 nm. (b) CM nanoshaving (2 × 2 μm2) image of NCD was made in air using NSG01 tip with applied force F = 1.5 μN. Overall image in TM reveal hole with depth h = 6 ± 12 nm. (c) CM nanoshaving (1 × 1 μm2) on MCD surface was made using NSG01 tip with F = 3 μN (k = 3 N/m). Overall image in TM (2 × 2 μm2) reveals absence of any changes on the surface. (d) The model illustrating wear of NCD grains by Si cantilever. CM nanoshaving makes NCD grains more rounded and their Lx values slightly increases. (e) The model illustrates formation of a depression in the NCD surface by the wear of NCD grains during AFM scanning in CM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211425&req=5

Figure 3: Wear of diamond substrates in contact mode AFM. (a) Two 2 × 2 μm2 CM scans with F = 3 μN were made in the central area using NSG01 tip with k = 3 N/m. Overall image in TM reveal holes with depth h = 20 ± 15 nm. (b) CM nanoshaving (2 × 2 μm2) image of NCD was made in air using NSG01 tip with applied force F = 1.5 μN. Overall image in TM reveal hole with depth h = 6 ± 12 nm. (c) CM nanoshaving (1 × 1 μm2) on MCD surface was made using NSG01 tip with F = 3 μN (k = 3 N/m). Overall image in TM (2 × 2 μm2) reveals absence of any changes on the surface. (d) The model illustrating wear of NCD grains by Si cantilever. CM nanoshaving makes NCD grains more rounded and their Lx values slightly increases. (e) The model illustrates formation of a depression in the NCD surface by the wear of NCD grains during AFM scanning in CM.
Mentions: Figure 3 shows the effect of AFM scanning on the diamond substrate itself and compares monocrystalline and NCDs in this aspect. Figure 3c shows that even when quite a high force (F = 3 μN) is applied to silicon tip (NSG01, NTM-DT) CM scan does not change the surface of the MCD. Figure 3a shows that similar force can modify the surface of the NCD. Overall image in TM reveals depressions h = 20 ± 15 nm deep. During this process the silicon tip is damaged. This is the reason for square like patterns in the image.

Bottom Line: We show that both diamond and proteins can be mechanically modified by Si AFM cantilever.We propose how to choose suitable cantilever type, optimize scanning parameters, recognize and minimize various artifacts, and obtain reliable AFM data both in solution and in air to reveal microscopic characteristics of protein-diamond interfaces.We also suggest that monocrystalline diamond is well defined substrate that can be applicable for fundamental studies of molecules on surfaces in general.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16253 Prague 6, Czech Republic. ukraints@fzu.cz.

ABSTRACT
Atomic force microscopy (AFM) in contact mode and tapping mode is employed for high resolution studies of soft organic molecules (fetal bovine serum proteins) on hard inorganic diamond substrates in solution and air. Various effects in morphology and phase measurements related to the cantilever spring constant, amplitude of tip oscillations, surface approach, tip shape and condition are demonstrated and discussed based on the proposed schematic models. We show that both diamond and proteins can be mechanically modified by Si AFM cantilever. We propose how to choose suitable cantilever type, optimize scanning parameters, recognize and minimize various artifacts, and obtain reliable AFM data both in solution and in air to reveal microscopic characteristics of protein-diamond interfaces. We also suggest that monocrystalline diamond is well defined substrate that can be applicable for fundamental studies of molecules on surfaces in general.

No MeSH data available.


Related in: MedlinePlus