Collagen - A Validation Sample for SAXS Systems
The performance of the SAXSpoint 2.0 system is evaluated by measurements of tendon collagen. SAXSpoint 2.0 produces data with excellent resolution in the entire angular range and delivers true 2D SWAXS images.
2D SAXS Studies of Collagen
Many modern laboratory SAXS systems are usually able to resolve the first order reflection of collagen at a scattering q-value of approx. 0.091 nm-1, corresponding to 67 nm d-spacing.
High-resolution measurements, i.e. obtaining SAXS data at extremely low scattering angles, can only be achieved with a clever collimation concept. Only in combination with a compact design, including shortest possible sample-to-detector distance high-resolution SAXS data can be obtained within short measurement time. These important requirements are realized in the SAXSpoint 2.0 system.
Fig.1 Collagen structure model
Experimental and Results
Collagen (turkey tendon) was analyzed with the SAXSpoint 2.0 system. The scattering curve of collagen has the first useable data point (qmin) at 0.026 nm-1 corresponding to a d-spacing of 240 nm (Fig. 3). Over a wide scattering angle range the scattering curve clearly shows well-pronounced peaks well separated from the noise level.
The SAXSpoint 2.0 system gives 2-dimensional SAXS data, which is of great importance for oriented (anisotropic) materials. Orientation phenomena of nanostructured samples can nicely be determined because the complete scattering information around the primary X-ray beam is detected.
Fig. 2 2D diffraction plattern of turkey collagen.
Fig. 3 1D scattering curve of the collagen sample extracted from the 2 D pattern.
Good to know
Collagen is the most abundant protein in mammals. About one quarter of all of the protein in our body is collagen. It has great tensile strength, and is the main component of ligaments and tendons.