X-ray imaging for quality assurance

Researchers from the Technical University of Denmark have developed a new method that uses X-rays to rapidly characterize materials contained within an indeterminate powder.

[Translation by Dr. Nachmani Moshe]
Researchers from the Technical University of Denmark have developed a new method that uses X-rays to rapidly characterize materials contained within an indeterminate powder. The new method has the potential to identify complex biological molecules such as proteins. Thus, the method has great potential both in the field of food production and in the pharmaceutical industry, where it could provide new opportunities for quality assurance of protein-based drugs, as one example.

Only rarely is it enough to read the statement of the content of the ingredients for a product in order to know exactly what all the ingredients of the product are. In fact, in order to get an accurate picture, you must be a professional chemist or have x-ray vision that shows you the molecular structure of the various substances inside the product. Researcher Christian Grundahl Frankær from the Technical University of Denmark (DTU), who is a chemical engineer, has managed to develop a method that allows him to use X-rays to look deep into biological samples.

The method is called 'Powder_diffraction' and involves exposing a sample to a powerful beam of X-rays. Once the beam hits the sample, it scatters (refracts) in the same way that light scatters when it hits a disco ball. This phenomenon produces a scattering pattern that reflects the internal structure of the material. Each individual material has its own unique pattern - a kind of 'fingerprint' - through which you can easily identify what the given material is by comparing the pattern to a known database.

Today, the powder diffraction method is used to identify simple substances such as sugars, salts and minerals, but the idea of ​​using this method to characterize complex biological molecules such as proteins is truly innovative. For this reason the new method has great potential both in the field of food production and in the pharmaceutical industry, where it could provide new opportunities for quality assurance of protein-based drugs, as one example.

"I tested different types of baby food compounds, protein powders and detergents. By taking a small sample of the powders of these substances and exposing it to X-rays, I was able to determine which substances are in the powder, and also what their concentrations are, within ten minutes. In addition, the analysis will usually also provide information regarding the method of production of the material," says the researcher. Therefore, the method is ideal for ensuring the quality of new products entering the market.

Proteins are large molecules with complex three-dimensional structures. The shape of the protein - or its crystal structure - may significantly change its properties. A protein such as insulin can have many crystalline forms, and the particular form in which the substance is found may affect its properties, such as solubility or its level of biological activity. This structure, in turn, may have an effect on how the protein reacts when it enters the body. For this reason, it makes a lot of sense to test the crystalline forms of different proteins, both during the production and the quality assurance phase of protein-based drugs, but this option simply did not exist or was uneconomic until now.

The lead researcher explains: "We have now demonstrated that the powder fractionation method can be used to characterize biological substances such as proteins. The results are not as detailed as obtaining a single crystal structure, which allows the general structure of the protein being studied to be deciphered, but they allow us to quickly and easily locate 'fingerprints' that characterize the protein and its crystal structure. This is very important knowledge when you work in the field of protein production.”

The method has great potential for improvements in a variety of areas, both at the quality level and in the production processes within the framework of all production systems involving solid materials. The application of the new method will make it possible to continuously examine changes - or differences - in various materials used in the production processes. "The great advantage of our method is that you can take samples directly from the production line. And then you have the results in your hands within 15 minutes and you can know exactly what the crystalline state of the produced material is. In addition, the X-ray beams we use can be produced using standard laboratory equipment," notes the lead researcher.

As an example of the method's effectiveness, the researchers note that a rapid analysis of a washing powder developed for the Danish market revealed a high level of zeolite material in the product, which is used to trap salts found in hard water that is so common in Denmark, while a sample from Morocco did not contain this material at all. Analysis of another washing powder revealed that the 'active oxygen' ingredient was simply the compound sodium percarbonate.

The news about the study