Creating reference data for studying type I collagen

Type I collagen (collagen I) makes up about 90% of the collagen in the human body, creating large fibers that form connective tissue. It is one of the proteins — collectively known as the matrisome — that make up the extracellular matrix (ECM), the material between cells that is paramount to cells’ structure and function.

Understanding collagen I is an important step for unraveling diseases associated with protein mutations in the ECM, as well as for mimicking the ECM in tissue engineering and for its use in cosmetics. As part of their larger efforts in matrisome analysis, Ralf Zimmermann and Mirko Nitschke created reference spectra for collagen I obtained from rat tails.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a common surface analysis technique in life sciences due to its ability to enable the investigation of differences in biological samples without the need for fluorescent tags or other sample labeling. However, because the technique bombards a sample with high-energy ions, molecular bonds in the material are broken, leading to its fragmentation.

Proteins are formed of a common set of amino acids, which results in similar fragments for different proteins. This necessitates the types of ToF-SIMS reference spectra Zimmermann and Nitschke created.

“We use reference spectra of pure proteins to identify protein characteristic signals,” Zimmermann said. “The spectral feature tables created as part of our projects can be used by other researchers to analyze cellular secreted matrices in different contexts — for example, to investigate the influence of morphogens on cell fate decisions.”

The researchers hope their dataset can also help push the boundaries of protein analytics by assisting machine learning techniques with matrisome pattern recognition.

“In our projects, we apply ToF-SIMS together with powerful machine learning pipelines to reveal pathogenic alterations of ECMs,” Zimmermann said. “The projects results could enable progress in the development of novel therapeutic strategies.”

Source: “Reference spectra of extracellular matrix proteins: Collagen I (COL1A1) from rat tail in positive and negative polarity,” by Ralf Zimmermann and Mirko Nitschke, Surface Science Spectra (2026). The article can be accessed at https://doi.org/10.1116/6.0005190 .

This paper is part of the ToF-SIMS of Homogeneous Materials Collection, learn more here .