Atomic Force Microscopy Probes for Force Spectroscopy

Force spectroscopy can be used to investigate the interactions and binding forces between individual molecules. In this technique, the mechanical properties of single polymer molecules or proteins, or individual chemical bonds, are measured, thus enabling several physical and biological processes to be better understood.

SCOUT 70 (uncoated), and SCOUT 70 RAl (aluminum-coated), SCOUT 70 RAu (gold-coated) are the three probe models available from NuNano, for performing force spectroscopy.

The NuNano SCOUT 70 is an all-purpose probe for performing imaging in non-contact/soft tapping AC modes. Similar to the entire range of NuNano AFM probes, SCOUT 70 offers excellent tip sharpness and dimensional tolerances.

The Scout 70 RAl model comes with an aluminum reflective backside coating to ensure improved signal. Thanks to the gold reflective backside coating provided in the NuNano Scout 70 RAu, it can be used in liquid/biological studies.

Applications

  • Force modulation
  • Non-contact/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

 

Atomic Force Microscopy Probes for Force Spectroscopy

Image Credit: NuNano

Note: The nominal values for resonant frequencies and spring constants are calculated based on standard probe dimensions and using well-known equations. Calculated dimensional variations are used for quantifying these ranges.

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

 

Atomic Force Microscopy Probes for Force Spectroscopy

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