Use of titanium dioxide in protein separation technique

Chemists from the National Institute of Standards and Technology NIST and Arizona State University have come up with a simple 'elegant' technique capable of separating proteins into convenient small pieces for analysis. The method of preparing the original sample uses ultraviolet light and titanium dioxide and can be ideal for 'laboratory on a new micro -lab (on-a-chip) device, the The device is designed to quickly analyze a small amount of biological samples.

Most proteins are very large and complex molecules made up of hundreds or thousands of amino acids, so they often have to be cut into smaller pieces that are easy to use for analysis. Today, this is mostly done by using special enzymes, called ' proteases ' that serve protein chains in ' famous ' places.

Illustrating the separation of proteins near the titanium dioxide surface: when illuminated with ultraviolet light, hydroxyl radicals are formed in water near the surface of the semiconductor and cut off proteins at places with amino acid proline.(Photo: NIST)

For example, protease tripxin cuts proteins at places with amino acids lysine and arginine. Analysis of the remaining pieces can determine the original protein. But the famous enzyme is ' picky ', requiring tight control of temperature and acidity, and the enzymatic cutting process can be time-consuming, ranging from a few hours to a few days.

To get another ' holistically ' method, the NIST team turned to a semiconductor material, titanium dioxide. Titanium dioxide has photocatalytic activity - when exposed to ultraviolet light, its surface is highly oxidized, converting nearby water molecules into hydroxyl radicals, chemical bases with short lifetime and High activity. In NIST experiments, titanium dioxide coatings are applied to a wide range of typical micro analytical devices, including microfluidic and silica particles in microflow reactor. By shining a strong UV light on this region, in the presence of a protein solution, a small ' splitting zone ' of hydroxyl radicals is produced, which quickly cuts nearby proteins in areas with amino acids. proline acid.

According to scientists, although the development work is still being done, the NIST photocatalyst catalyst has brought some advantages for the enzymatic separation of proteins in the traditional way. This technique is particularly insensitive to temperature or acidity and does not require any reagents other than dissolved oxygen in the solution.

This technique has a simple preparation, easy to integrate into many types of instruments and equipment, and titanium dioxide, an inorganic substance, will basically exist forever under different conditions - while enzymes must be Carefully handled and stored in a temperature controlled environment. Desirable acid amono, proline, is quite sparse in most proteins, but it is found in key places, such as sudden turning points in the molecule, and this will support fecal work. . In addition, the technique was done very quickly - in the experiment with protein angiotensin I, the team obtained detectable splits in just 10 seconds.

Thanh Van