Force Spectroscopy: AFM Probe Imaging

Force spectroscopy allows the investigation of the binding forces and interactions between individual molecules. The technique involves quantifying the mechanical properties of single polymer molecules or proteins, or individual chemical bonds, offering better insights into numerous physical and biological processes.

NuNano offers three probe models for performing force spectroscopy: SCOUT 70 (uncoated), SCOUT 70 RAu (gold-coated), and SCOUT 70 RAl (aluminum-coated).

The SCOUT 70 from NuNano is a multipurpose probe for imaging in AC modes (non-contact/soft tapping). This probe exhibits excellent dimensional tolerances and tip sharpness, which is typical of all AFM probes from NuNano.

The Scout 70 RAu model has a gold reflective backside coating that enables its use in liquid/biological studies. The Scout 70 RAl is provided with an aluminum reflective backside coating for enhanced signal.

Applications

  • Force modulation
  • Non-contact and soft tapping modes in air

Cantilever Specifications

Table 1. Source: NuNano

Parameter Nominal Range
Spring constant (N/m) 2 0.5 – 3.5
Resonant frequency (kHz) 70 45 – 80
Shape Rectangular
Length (μm) 225 223 – 227
Width (μm) 30 29 – 31
Thickness (μm) 2.5 2.0 – 3.0
Material Silicon (n-type, antimony)
Resistivity (Ωcm) 0.02 0.015 – 0.025

 

Image Credit: NNano

NB. NuNano calculates nominal values for spring constants and resonant frequencies using well-known methods and based on typical probe dimensions. The ranges are measured using calculated dimensional variations.

Tip Specifications

Table 2. Source: NuNano

Parameter Nominal Range
Radius (nm) 5 < 10
Height (μm) 6 5 – 8
Set back (μm) 7.5 6.5 – 8.5
Shape Conical
Cone angle (°) 25 15 - 40
Material    
Resistivity (Ωcm) 0.02 0.015 – 0.025

 

Chip Specifications

Table 3. Source: NuNano

. .
Length (mm) 3.4
Width (mm) 1.6
Thickness (mm) 0.3
Cantilever anchor Yes
Alignment grooves No

 

Image Credit: NuNano

Coatings—SCOUT 70 RAu

Table 4. Source: NuNano

. .
Frontside / Tip none
Backside / Reflective 5 nm Ti
50 nm Au

 

Coatings—SCOUT 70 RAl

Table 5. Source: NuNano

. .
Frontside / Tip none
Backside / Reflective 40 nm Al

 

Force measurement in the field of biological sciences can be performed efficiently using NuNano’s Tipless Silicon Nitride AFM probes that include a gold reflective coating.

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