Bio and Nano Technologies Helping to Learn more about Human Being
Humanity seeks new worlds, both in macro and microcosm. Scientists from all over the world are trying to create better tools for the investigation of the world. In this article, we consider the development that nominated for RUSNANOPRIZE in the field of biomedical nanotechnology, namely, those which help to get more information about the living material.
Spherical DNA - visualization of gene activity in living cells
One of the works is about the unusual shape of the packaging of DNA molecules. It was found that the sewing threads of short DNA strings to gold nanoparticles makes these short strings less visible to the security systems of living cells. As a result, the universal nano-sensors were created. The structure of this sensor is similar to a brush - solid gold nanoparticles are inside and "hairs" of DNA, that sticking out in all directions.
Firstly, he operating principle of the sensor is based on the uniqueness of the DNA code, i.e. a unique sequence of nucleotide blocks that composing the polymer chain. Secondly, peculiarity of DNA is that certain blocks may be "glued" together. If two polymer chains have short complementary areas, i.e. those areas that can "stick" to each other, these two chains may be connected with each other, but the connection will not be strong. If the two strings are completely complementary sequence, they "stick together" with high strength.
In this case one of the two complementary chains is sewed to the gold particle, and the second one holds only by their complementarity. Moreover, this second thread carries a fluorescent label. When labeled chain is in a bound state, a label is not active. But if this labeled chain detaches from its "second half" and will be free in solution, then a label can be registered. Complementary DNA chain can disconnect only if there is other thread of DNA or RNA next to it that carries the exact same complementary sequence of nucleotides.
The action of a sensor is based on this principle. Getting into the into the cell, this "brush" begins to "feel" the presence of DNA or RNA with complementary sequences in the cell. Let us recall that genes are encoded in the sequence of structural DNA blocks, i.e. sequence that indirectly define the structure of proteins. And a molecule of RNA, it is just one of the "intermediaries", it carries exact complementary "cast" of the sequence of a single gene. If there is RNA with a given sequence in the cell, it means that the gene with a complementary sequence is currently working, reading out and involved in organization of the cell life.
Thus, the gold nanoparticles with DNA as a thread spherical brush –is a sensor of the activity of specific genes. We add such particles into the cell and if the gene is active, we register the signal of the fluorescent label.
Diagnosis of diseases . Exosomes
One of the most popular and understandable to most people kinds of research information of a living organism is information about the presence and severity of the disease, i.e., diagnostic methods. Diagnosis of diseases is usually carried out at the organismal level because people usually do not know what's going on in their cells, but they notice the problem when the disease affects the large functional blocks, such as systems of bodies, organs, the relationship of different parts of the body. Perhaps the most common subject for diagnostic tests is blood, the fluid that is constantly moving around the body, nourishes, oxygenates and clean organs, tissues and cells of toxins.
One of the works is devoted to the diagnosis of cancer by determining the blood exosomes. This nanosized membrane vesicles that are secreted into the blood by any cells, but the contents of exosomes is different in cancer cells. Therefore, by the presence of specific exosomes in the blood you can detect tumors, even at an early stage of the disease, when it is still impossible to see them by the other methods. For many types of cancer diagnosis stage fundamentally influences the prognosis for the patient: if detect a tumor early, outlook is positive, if later, then it is not.
The well-known function of blood is protective. The humeral immunity is millions of special protein molecules, such as antibodies, each of which recognizes its specific target. If this target appears in the blood, a protective molecule "sticks" to it, and apposed complex finds and destroys specific cells. But the balance of the ratio of protective antibodies with different specificity can characterize the state of the organism.
In one of the applications there is a immunosignature technology, which can be specific for a number of diseases. "Signature» is a figure, the combination of color signals of several hundred thousand pixels. Each point is a specially synthesized and attached to the chip surface a piece of protein (peptide), which may be specific for one of the antibodies. A vast array of peptide points is applied on chip in the factory.
Since the size of each point is measured in microns and the distance between the points is just 1 nm, all chips are miniature; one blood drop is enough for studying! Figure that appears on the chip can help simultaneously diagnose up to 50 common diseases, including the most common cancers, type 1 diabetes, Alzheimer's disease and many others.
Biosensors for agriculture
The same approaches and principles that are applicable to the study of human health, are also applicable to the study of animals. Biosensor technology to detect microRNAs (microRNAs are mainly informative component of exosomes in the above described diagnostic approaches), as well as modern methods of visualization of protein-protein interactions (which are the basis of chips with immunesignature) and proposed as a diagnostic tools for the veterinary practice.
Moreover, researchers adapt a wide arsenal of nanoscale sensors to study and monitor food quality. For example, the ratio of specific gases inside the package with the products in continuous monitoring mode can help determine the extent of damage. And the cost of this built-in sensor packaging is quite small, even compared to the cost of packaging, or even the cost of the product.
DNA sequencing and the prospect of creating hybrid organisms
Two applications are about the technologies that can form the basis for construction of synthetic biomachines in a consequence. One of the technologies was originated from observations of the biological systems, such as bacteriophages and viruses that hunt for bacteria. It appeared that bacteriophages created an unusual type of rotary engine, which they use to minimize their DNA. Rotary motor is a versatile building block, which is understandable for non-biologists engineers, and therefore, this is one of the first candidates for incorporation in the future of biosynthetic organisms.
Membrane pore structure was also spied on bacteriophages. It allows jam long DNA pieces through the membrane with the proviso that they have "correct" nucleotide sequence in the chain. On the basis of this pores is now developed a method of sequencing, i.e. determining nucleotide sequences in the DNA chain.
There is also another technology for the problem of determining the nucleotide sequences of nucleic acids RNA and DNA. It is based on the determination of the local molecular conductivity and nucleotides in the nucleic acid chain can be distinguished by this parameter. Feature of the technology is that it uses nanoelectronic devices based on grlerodnyh nanomaterials, such as graphene and carbon nanotubes. In the future, these devices can be embedded in living cells. These carbon-electronic components are fully synthetic and analogs of them has not yet been found in the wild.