Toothpick: A new molecular tag that identifies minerals and teeth

Considering a lot of plant viruses to understand the causes, material scientists at the University of Technology and National Standards have discovered a small biological molecule that binds to one of the host crystal structures. Key of the body - it is a calcium compound that is the basic component of teeth and bones.

The researchers said the new molecule could be a reliable means of application in many therapies as well as diagnoses related to teeth and bones.

Although teeth and bones have slightly different mechanical properties, their basic structural component is a crystalline compound of calcium phosphate called hydroxyapatite. Subtle changes in how the crystal structure is formed have made a difference between them. The identification and control of the characteristic crystal formation process is of utmost importance to biomedical researchers to explore issues including reconstituted teeth to treat tooth decay, combined. Artificial joints and bone tissue cultured to replace bones and joints, as well as cellular therapies for bone tissue redevelopment.

Hydroxyapatite crystalline sedimentation in the image of human teeth is bright green in areas where a new NIST peptide is attached to bind to the above compound.Chain of peptides linked to fluorescent dye to create images.(Photo: NIST)

However, there has been no specific experimental method to detect the formation of hydroxyapatite in living systems or tissue samples. Material scientists can identify crystal structures with high reliability thanks to its X-ray dispersion model but this is a complex process that requires relatively pure and completely research samples. cannot be applied to live systems. There are a number of widely used chemical tests, such as the von Kossa experiment, which also has some destructive tests. More importantly, they are simply to check for the presence of calcium or phosphorus. They can distinguish between non-crystalline calcium phosphate deposits (precursors of hydroxyapatite crystals) and hydroxyapatite crystals.

In order to obtain a less specific and less specific exploration tool, the NIST team used a relatively new technique called 'phage display' that was able to quickly create and screen large numbers of biomolecules. for specific interactions. Phage is a primitive group of viruses that often encounter bacterial poisoning. Some simple phages can be genetically modified to randomly regenerate short sequences of amino acids - small protein molecules called peptide chains - on the outer shell as their binding point.

The cultured phage group synthesizes billions of random peptide chains. If they are taken to the target surface - hydroxyapatite crystal in this case - and then removed, the rest will be those that tend to stick. The clones of the remaining animals and then repeating some cycles with the final increased conditions will help isolate many 'bright' peptide chains used in later tests to determine the relationship between them and goals.

According to a recent paper, the NIST team used this technique to identify a new peptide chain formed from both the chemical structure and the crystal structure of hydroxyapatite to bind to the surface of the material. The ability to identify the specific peptide chain of hydroxyapatite, according to the researchers, will be exploited as a nondestructive card to control the mineralization of teeth and bones in therapeutic applications as well. as diagnostic.

Quote: MD Roy, SK Stanley, EJ Amis and ML Becker. Identification of a highly specific hydroxyapatite-binding peptide using phage display. Adv. Mater. 2008, 20, 1830-1836