The main task of modern personalized medicine is to identify the risks of disease in a particular person. This will help to prevent diseases in advance and prescribe adequate treatment. It is possible to examine in detail the whole human body to understand what is affected in it, but it is an expensive process that takes a lot of time. That's why scientists have developed bio chips that reveal hundreds and thousands of bio markers in one analysis - compounds that indicate the presence of any disorder or susceptibility to disease.
History of biological microchips
The idea of developing bio chips appeared in the late 1980s and belonged to several groups of scientists, including those from the USSR, Yugoslavia and the United Kingdom. In the Soviet Union, Academician Andrei Mirzabekov, Director of the W.A. Engelhardt Institute of Molecular Biology of the Russian Academy of Sciences, proposed the idea of bio chips as an alternative to the then complex method of deciphering DNA sequences. Mirzabekov postulated the possibility of placing short DNA fragments - probes — on the flat surface of micro-matrixes in three-dimensional hemispherical cells of hydro gel. The cells with probes were placed on the substrates in a strictly ordered form. Since the localization of the probes in the cells is known in advance, the interaction of probes with the analyzed DNA molecules made it possible to determine the structure of extended DNA regions. Thus, for the first time in the world, the theory of sequencing on DNA bio chips was proposed and substantiated.
A biological microchip is a matrix of cells, each of which contain a specific probe (DNA molecule, protein, Glycol, low-molecular weight ligands, etc.) that recognizes its target in the sample, for example, a drop of blood.
Retreated molecules of the sample inserted into the bio chip chamber and marked with fluorescent dye is able to penetrate the cells and interact with specific probes. When irradiated with light of a certain wavelength of the bio chip surface of a cell, in which there was a specific interaction, fluoresced. This fluorescence can be registered with the help of a special microscope analyzer. Then calculate the intensity of signals in each cell and, knowing the algorithm of signal processing, determine the presence of a specific target in the sample under study — microorganism, virus, mutation, chromosomal rearrangement, cancer marker, allergen, etc. This process makes it possible to choose an adequate strategy of treatment of the patient promptly.!!!!!!!!!!!!!!!!!!!
The matrix of bio chip cells is made by transferring droplets of a mixture of probes and hydro gel with the volume of 0.1 nanoliters from wells of the micro plate to a plastic substrate
This is done with the help of ultra-thin metal rods of a mechanical robot. Such droplets can move and merge on the hydrophobic surface of the substrate, so it is very important to fix them through the reaction of photo polymerization with the formation of covalent bonds between the droplets and the substrate with the active groups of the substrate, and between the molecules of the probe and monomers of the hydro gel. For this purpose, the substrates are irradiated with light of a certain wavelength under strict conditions: temperature, humidity, irradiation time, presence of inert gas displacing oxygen molecules. Thus, under the influence of ultraviolet radiation there is a joint polymerization of molecular probes (DNA fragments, proteins, etc.) with the main components of the hydro gel. In the course of the reaction, the molecular probes are covalent attached to the growing polymer chains and evenly distributed throughout the gel volume, thus immobilizing the probes.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
The matrix of cells of bio chips are formed on the glass covered with a mono molecular layer of substance containing active chemical groups interacting with the applied probes.
Technology of hydro gel bio chips IMB RAS uses plastic substrates, which significantly simplifies and reduces the cost of manufacturing of matrices. Russian engineers created molds for the production of substrates and reaction chambers of bio chip by injection molding which ensures our technological independence in this field.!!!!!!!!!!!!!!
The key aspect of domestic technology of bio chips is Use of a special hydro gel In which molecular probes are placed.
The immobilization capacity of the probes in the hydro gel cells of the bio chip increases by several orders of magnitude. This makes it possible to register signals in the chip elements, which are 10-100 times higher than when immobilizing on flat glass matrices, and, accordingly, to create and use inexpensive bio chip analyzers. These helps to detect clinically significant markers with very high specificity, giving the result in a “yes — no” format.