DNA MICROARRAY

             
                           Gargi Pal
           Bengal school of technology
                (A college of pharmacy)
           

1. INTRODUCTION

All organisms have DNA, a molecule that contains all the information essential for the growth and function of an organism. Find and the information encoded in DNA is understood and how it is interpreted atmosphere. It infers assumptions from a guess-driven effort. Effort arises because each experiment focuses on the entire field gene outbreaks, allowing the relevant genes to express themselves, are often surprising. Also, what used to be primarily wet science is known in large part information science. The highly parallel nature of microarrays used to make them biological observations indicate that most experiments produce more data the examiner can probably explain. In fact, from a statistical standpoint, each gene measured in a microarray is a very different variable. Simple molecules can bring amazing biological diversity to life, which is a goal all life scientists share one way. Microarray provides an unprecedented view DNA is a rich way of investigating biology and thus living systems. DNA is one a physical molecule that is capable of encoding information in a linear structure. Cell publish information from different parts of this structure based on context fashion. DNA encodes for genes and regulates whether regulatory elements a are genes on or off. For example, all cells in the human body still have the same DNA there are many types of cells, each expressing a unique configuration from DNA to genes. In this case, DNA can be described as existing for either number of states. A microarray is a device used to study the state of DNA.

         Microarrays have a transformational effect on biological science. In the past biologists had to work very hard to produce small amounts of data used to detect an estimate with one observation at a time. With the advent of microarrays, individual experiments create thousands of data points or observation. Parallel examination number of hypotheses where data may or may not and support for non-payment is not known beforehand. To take advantage of additional information in microarray data, repositories have been created so that people can make them available to a wider community, submit their tests researcher with questions for search (gene expression omnibus GEO, Array Express).

KEYWORDS: Biochips, microarray, hybridization, gene expression, DNA diagnostics, Peptide nucleic acid, oligonucleotide, miniaturization, Protein arrays.

2. DNA MICROARRAY TECHNIQUE 

An array is an orderly arrangement of samples where matching of known and unknown DNA samples is done based on base pairing rules. An array experiment makes use of common assay systems such as microplates or standard blotting membranes. The sample spot sizes are typically less than 200 microns in diameter usually contain thousands of spots.

Thousands of spotted samples known as probes (with known identity) are immobilized on a solid support (a microscope glass slides or silicon chips or nylon membrane). The spots can be DNA, cDNA, or oligonucleotides. These are used to determine complementary binding of the unknown sequences thus allowing parallel analysis for gene expression and gene discovery. An experiment with a single DNA chip can provide information on thousands of genes simultaneously. An orderly arrangement of the probes on the support is important as the location of each spot on the array is used for the identification of a gene.

3. STRUCTURE OF DNA MICROARRAY

Samples are arranged on the array in spots of less than 200 micrometers in diameter. Each array can contain thousands of spots neatly ordered into rows and columns, and represents one gene. The spotted samples are called probes and are traditionally placed on a support consisting of materials such as glass slides, silicon-thin chips or nylon membranes. Bead arrays are also being used where the arrangement is comprised of microscopic polystyrene beads, each forming a specific probe. Individual samples can be identified by their placement on the array as the orderly arrangement of spotted samples on a solid structure provides an easily determined location for each gene being analyzed. The location of the gene is then recorded onto a computer database.

4. GENE DETECTION BY HYBRIDIZATION

The purpose of a microarray is to examine the expression of several genes in response to some biological disruption, microarrays are typically interrogating the concentration of molecules in a complex mixture and acting as such can serve as a powerful analytical tool for various experiments. It is useful to examine the structure of DNA and how it occurs. The unique structure of these molecules plays a role in identifying them. Although DNA is quite informatively complex, its general structure molecules are actually quite simple. DNA is composed of four chemical building blocks. The bases are called: adenine, cytosine, guanine, and thymidine (for short as A, C, G, or T). These building blocks are also known as separate subunits of nucleotides. The strands of DNA have a sugar phosphate backbone that they contain. The cases are covalently linked to the fact that they form a chain. Because it can have four bases, it is possible to use them to encode information based on form order signs of the event. Actually, from the information point of view, DNA it has a potential data density of 145 million bits per inch and is treated as the substrate for the computation from which software is called software.

Like strings of text in a book, strands of DNA instructions Such information can be encoded in any direction. The amount of DNA, and thus the sequence amount, differs from the organism to organism. For example, the microbe Escarichia coli has 4.5 million bases of sequence, where human cells have about 3 billion bases. Exactly how much, the biological information encoded in these   sequences is unknown, representing among the deepest mysteries of biology, however, microarrays provide a way to obtain clues. In most cases cellular DNA has not only one strand but two strands. Two varieties parallel to each other are joined by hydrogen spacing. The action within the base forms a structure in the cell.

The structure is helical, a spiral staircase is similar where the bases are connected and interact with each side to build a ladder on a plane. In addition to hydrogen bonds reverse strand bases, overlapping and proximity of bases to each other. The stacking interaction is called the second type of inductive energy. It respects the durability of the double-strand structure. The bases of one strand interact according to one base of the other strand.

Therefore, set a pair of rule rules, such as A pairs with T and C pairs with G. Thus, if anyone knows, the order of a strand, by definition, the order of one. This property has profound consequences in the study of reverse strand biology. It uses the cell to make its own replication. Such is the interaction between the bases is noncovalent, containing only hydrogen bonds. Varieties can be essentially the same, in a continuous, only hydrogen bond molten and separated, thus opening the way for a copy process. Read each single strand and recreate the second complementary strand for each half of the pair forms a new double-stranded molecule for each cell. The mechanism by which cells express genes. It is opened by strand gene expression machinery to synthesize a large number of RNA copies. RNA transcript is the same sequence with genes the exception is that uracil (U) replaces T, although hybrid binding rules are similar (both U and T can combine with A).

This property of complementarity is also used for gene expression on microarray. Like strength can separate strands separately in a single molecule, the process reverses in the case of such single strands. Couples can be made to complement each other. Trapping is complex. This process is called hybridization and its basis for many assays or experiments in molecular biology. In the cell, hybridization occurs various biological processing centres, where laboratories are complementary. And thus, hybridization is at the centre of many in vitro reactions and analytical strategy. Molecules can come entirely from different sources but if so matches, they will be hybrids.

5. HYBRIDIZATION IS USED TO MEASURE GENE EXPRESSION

Hybridization-based methods have been used to determine nucleic acid sequences. As a standard strategy for decades.  Most accepted and understood standard for measuring gene expression is a hybridization-based assay called the Northern blot. Microarrays were obtained from blotting assays. So, it is useful to understand the basics of how they work and explain the source of something glossary. Northern blot is also a common method to verify results from research on a microarray.  The purpose of a Northern blot is to measure the size and abundance of RNA. Transcripts from one gene to compare expression of one gene under different. Under the conditions, cellular RNA extracts are prepared from different batches of cells or tissue and fraction with the size of agarose gels before being transferred into a nylon membrane are quantitatively bound and stored in the nucleic acid of the membrane pattern of RNA from gel. The result is a membranous pore with RNA from different samples in different areas of the membrane. Expression volume the gene level of interest in each sample, a radioactive DNA probe complementary was drawn into the gene of interest. After implementing the investigation in the membrane, hybridization checks and messengers will appear in ribonucleic acid (mRNA) from the gene of interest. In this way, both positions RNA and relative abundance will be detected in fraction samples. The amount of radioactivity captured by each sample of membrane is one a readout of the relative expression level of the gene of interest between the two sample. In this scenario, the mRNA sample in the membrane is a complex mixture.  Molecule of unknown density. Occasionally occupying isolated areas sample RNA has a target transcript that will be published upon discovery. It is a hybrid, so the search is known, and the target is detected hybridization. Although this process is powerful, it is limited to a target question undoubtedly. To measure the second gene, the membrane must be washed under condition that inhibit hybridization and cut off the membrane of radioactivity, so that can be scolded for other goals.

6. NEW TWIST FOR AN OLD TECHNIQUE BY MICROARRAYS

Microarrays provide a way to reverse multiple genes simultaneously and cross-measure them. This slows down the process. Instead of a label that is known and searching for a complex of unknown mixture to highlight single target, labelled microarray method the complex mixture that is in solution and uses a two-dimensional surface molecules or probes as readouts in different locations. In this context, the cellular RNA mixture is labelled, forming a complex mixture with an unknown label. Complementarity the mindset between molecules and array probes in complex mixtures. The hard surface captures it, resulting in annealing and hybridization. So that capturing the labelled molecules on surfaces. Unhybridized molecules were first washed away prior to quantification.

 Although membranes have been used in the past to create this macroarrays for screening libraries of clones, usually with detection individually expressed genes microarray breakthrough mini-authorization. The interaction between a search and its target is a compelling trap. For example-while many genes are expressed at low levels, sensitivity is often a problem.

Most searched the defendants will consider, mid- 1980s found that reducing the size of a mandatory target did not reduce sensation the importance or accuracy of a mine and actually leads to an increased sensitivity. Thus, minimization is possible. As the spot size decreases, the compartmental ownership of the immobilized probe is dependent only on the concentration of the relative target molecule in solution. Microarrays operate based on this basis. Other developments have contributed to efficient parallelization through miniaturization. It is used as a medium to substitute for layers of glass with perforated filters. Capturing nucleic acids in an array format means small hybridization volumes can be used. Thus, the rate of hybridization is even smaller depending on the concentration. High rates of volume hybridization and increased sensitivity. Other than this, hard glass surfaces have low inherent fluorescence, which uses fluorescent. Micro-adaptive methods for color and label sampling. Copy, they allow for the efficient magnitude of a highly parallel miniaturized assay. Many groups have developed and implemented these concepts, commute combinations, robots and genomes to develop new assays to measure gene expression parallel. 

The traditional assay method has the advantages of using protein array technology, including simultaneous detection of multiple analytes, sample depletion and re-material volume and high production of test results. This subject to ligands to denaturation, however has delay production of a steady, reproducible biochip platform, limiting most array assays by using manpower or, at most, semi automated processing technique. A design for biochip memory devices based on known materials and existing theories presented. The formation of these memory systems depends on the self-assembly of nucleic acids junction system, which acts as a scaffold for polyethylene-rich molecular wire units. A molecular switch to control currents based on charge formation transfer complex. A molecular-scale bit is presented, based on the oxidation-reduction capability atoms or groups of metal. The amount of "bits" readable by these elements is 3x10^7 angstrom and must be operated electronically over short distances. After the selection of the appropriate biochip substrate, the biochip surfaces were chemically modified and evaluated to enable optimization of the Biochip fabrication method for various test panels.

Each biochip contain one to several thousand to thousands of gel drops in support of a glass, plastic or membrane, each containing about 100 microns in diameter. Each piece of a DNA strand, protein, peptide or antibody is inserted into each piece into a stitch. This is to identify a specific biological agent or biochemical signature. These drops are at a known position. Therefore, when a sample reacts, the reaction space can be identified by identifying the sample.

Biochip system can identify infectious disease strains when testing protein arrays and in less than 15 minutes and less than two hours when testing nucleic acid arrays.

7. DIFFERENT TYPES OF ARRAYS

There are basically three types of microarray technology for widespread use.

Most in the laboratory: containing pre-synthesized oligos present in microarrays or PCR products are imperfectly deposited as robots on a chip surface. One of the few oligonucleotides synthesized on the chip surface and another in situ. An array-like synthesis platform created by Agilent and NimbleGen.

Though each technique effectively functions as a genomic readout, each with distinct characteristics that confer advantages or disadvantages in a given context. Parallel form of measurement of DNA and RNA will continue to change and develop; But these three plots currently the forms are ubiquitous. 

Spotted microarrays:

Spotted microarrays are and continue to be the first widely available array platform to be enjoy wide usage. Made in the laboratory of Pat Brown, they are made of glass. The microscope slide contains a library of PCR products or long oligonucleotides. Printed using a robot equipped with nibs capable of awakening DNA from microtiter plates and microns are deposited on the glass surface with precision. Since their inception, the demand for microarrays has gone beyond availability. Because Brown laboratory has spent every aspect of distributing the technology. All protocols include robots required for array production and planning and in use, many academic laboratories invest resources to produce this array locally. These include performing PCR in addition to making or purchasing robots, oligo design and synthesis to make probes for stained glass. Original principle with which array function is quite simple, and all necessary reagents are some are available to most researchers with initial investment. But apart from this researcher are praising the benefits of having technology in their hands, because to highlight this aspect of spotted arrays is to show nonuniform nature of spotted microarray. Because there is no creator, a source of material, or a similar method of production, variability exists between batches of microarrays, and when planning observation or comparing tests should be considered from various array sources.

Spotted microarray is essentially a comparative technique. They are used to check the relative density of targets between the two samples. Complex model labelled comparatively before having a unique colored fluorescent tag before mixing together allows microarrays to compete for hybrids in spots. In this way, differences between samples can be observed. On a per-spot basis, occupation of a fraction of the spot is aligned by all sample shows relative concentrations of genes or targets at baseline complex mixture. Therefore, for any probe in the microarray, one gets a readout the target is the relative density between the two input samples. Due to this reason, spotted microarrays are often called two color or two-sample arrays.

Affymetrix gene-chips:

Affymetrix GeneChips is the most ubiquitous and permanent commercial array stage access. The array contains a 25-mer oligonucleotide in situ on the surface of a glass chip. A photolithography mask, used to manufacture semiconductor chips, light-guided DNA synthesis, are used to control chemistry. Such nuclear sequences are formed once at a certain point on a solid substrate or glass chip.

Current chips have 6.5 million unique detection in the area of 1.28 cm2. Very accurate nature of lithographic approach. The square of the probe allows the creation of a compact matrix of patches.

This would be without using a single sequence to search for expression of each gene common to spotted arrays, Affymetrix Express - employs a set of probes to measure of gene. The probe set of a gene consists of two types of probes to measure the gene of interest, correct match and mismatch (MM) checks.

The correct match probe is selected, the gene is precisely matched and designed to represent an exemplary sequence gene.  Although each probe is unique, probes can sometimes overlap. A match checks are similar to true match quests except they have one the search center does not match any base. In essence the same inequality 25-mer sequences are very disruptive to hybridization. The intention of mismatch probe to serve as a negative control for background hybridization. A general check set consists of 11 perfect match probes and 11 mismatches probes. The location of the probe for a single gene in the array is chosen by a random process protect against local hybridization artifacts that might otherwise affect all investigations for genes if they are clustered together. Since most of the spotted arrays use only one probe in each gene, local hybridization artifacts may be a problem. Reading gene expression levels is not a perfect match and mismatch probe readings should be shortened. Although there is a standard method of Affymetrix summarizes 22 readouts to obtain a single number for gene expression, several are available. Affymetrix GeneChips are a single sample microarray (known as a color or single channel). These arrays measure the relative abundance of each gene in a unit sample. In this way, one can test whether a gene is expressed at higher or lower levels than some other genes in the same sample. If samples are compared, separate chips must be performed for each sample and the data must be adjusted by scaling or generalization before comparison.

8. APPLICATIONS OF DNA MICROARRAY

Complete sequence of human genome and subsequent intensive discoveries versatile variations provide the necessary prerequisite markers to minimize its details genetic variability in drug response. Improvement in sensitivity and accuracy of DNA microarrays allow detailed and accurate verification of the human genome. It is progressing possibility of significant improvement in healthcare management by improving diagnosis and target Molecular Medicine. In limited use today, the pharmacogenetic approach will be integral part of medical monitoring and health management before allowing patient levelling treatment, with the ability to eliminate adverse drug reactions.

Biochip technology can be applied in biological, proteomic and glycaemic research, as well as pharmacology and toxicology another many other fields. However, common applications are in the determination of gene expression in human cells and tissues. Worldwide gene expression analysis has helped identify important genes and signalling pathways in humans’ malignant tumours and hopefully microarrays will step off '' the bench (laboratory) bench to the bedside (of patient)”.

Biochips (e.g. GeneChip, CYP450, Electrochemical biochips, Protein biochips, microfluidic biochips and nanotechnology-based biochips) are playing an important role in molecular diagnosis, and their application to care diagnostics from the point is expected to facilitate the development of individual people treatment. Gene expression profiles should advance personalization by microarray cancer treatment based on molecular classification of benefits.

Biochip refining with the advent of nanotechnology, more molecular diagnostics will contribute development of personalized medicines.

Biochip technology: standard diagnostic tool for human, veterinary medicine

Biochips will enter into clinical medicine in the following years. High-throughput development 'Biochip' technologies have dramatically increased our ability to study biology and molecular discovery disease based. Biochips enable extensive parallel molecular analysis to be performed in one short format with very high throughput. Every major diagnostics laboratory will provide genetic testing using this method. Infectious diseases can be detected by biochip systems. It takes less than 15 minutes when testing the protein array and less than two hours when testing nucleic acid array. This system can be used in hospitals and other laboratories as well as in cases. Technology provides a point of care diagnostic system that saves time and money by comparison in current systems, this requires sending samples to a centralized laboratory for confirmatory diagnosis. Single nucleotide polymorphism (SNP) will be used in cancer research as various biochips technologies including analyser of disease predisposition, cDNA microarrays concentration, function activities or interaction of proteins with proteometric biochip will be used for global gene expression patterns, tissue microarray as used cell types or tissue as well as clinical endpoints associated with molecular targets. Biochips readout of activity levels of thousand of genes and proteins will be facilitated in diagnostics of cancer. 12 tumour markers’ (TMs) biochip diagnostic (C12) system has proved useful in some previous studies but its value for colorectal cancer (CRC) has not only been systematically investigated.

Biochip sensors are used for rapid and sensitive detection of viral diseases. Biochip may be a potential tool for the diagnosis of mastitis pathogens in milk and to provide information for more effective treatment for the treatment of mastitis. Biochip was enabled detection of 7 common species of mastitis pathogens, including Corynebacterium bovis, Mycoplasma bovis, Staphylococcus aureus and Streptococcus spp. S .  agalactiae, s.  bovis, S. Dysagalactiae, and  S, uberis  within 6 hours. This technique was based on DNA amplification of genes specific and 4 basic steps for target pathogens include: DNA extraction of bacteria, polymerase chain reactions, DNA hybridization and colorimetric reactions.

Biochips for adding and measuring biochemical properties:

In the last two decades, the biological and medical fields have improved a lot. Development and capable to identify and quantify biomolecules of biomarkers and biochips. Biochip platform on gold can be made by nanoscale biotinylated self-assembling structures for the streptavidin surface or the protein containing free NH2 group are involved in N-     hydroxysuccinimide (NHS) active surfaces. Potential application of tumour necrosis factor (TNFα) serodiagnosis of hemophagocytic lymphohistocytosis (HLH) has been investigated. Conversation of biochips were optimized using indirect TNF α antigens and TNF α antibodies immunofluorescence method.

Biochip development for polymorphism analysis in biotransformation system genes:

Large-scale population research, diagnosis of genetic disturbances in multifunctionality screening of polymorphic loci for diseases, pharmaceuticals with special sensitivity development of an effective, accurate and rapid method of analysis is essential for preparation, identification too many mutations at once. A super perspective way to solve this 

problem is method of allele specific hybridization with biochip.

Biochip to detect biowarfare agents:

Biochip can also be used to identify biological warfare agents. Simple sample preparation standard operating protocol and a portable biochip reader smaller than a lunchbox. A system suitable for field use by first responders, military personnel, and medical technicians. The system uses polymerase chain reaction (PCR), a universal method for replicating billions copy with a piece of genetic material. The trace amount of PCR DNA can be replicated in levels where they can be detected in biochip systems. A sample biochip is applied for testing, it is then given to a reader and scanned using patented side illumination laser technology to detect feedback site. The automated algorithm determines the agents present in the sample.

Biochip for diagnostic testing:

Biochip can be used for rapid diagnostic tests because Biochip allows technicians to perform tests many different agents at once. Technology holds great promise for rapid diagnostic testing. Biochip allows technicians to test for several different agents at once. Under current development, the respiratory syndrome chip which tests for strep throat, Influenza A and Influenza B. Symptoms of patients allow physicians a faster and more accurate diagnosis when displaying symptoms in many different diseases. The system is a rapid system in the TB-Biochip oligonucleotide microarray to identify mutations related to rifampin (RIF) resistance in mycobacteria. Lack of a sensitive immunoassay for serum prostate-specific membrane antigen (PSMA) sensitivity inhibits its clinical utility as a diagnostic / symptomatic biomarker. An innovative protein biochip immunoassay was used to determine and compare serum PSMA levels in healthy men and patients with either mild or fatal prostate disease. 

These preliminary findings may be one that leads to serum PSMA malignant prostate disease warrants additional evaluation of the surface-enhanced laser desorption / ionization PSMA immunoassay to determine the clinical utility. An antibody sandwich assay with various capture antibodies on the surface of a chip and with detection antibodies associated with it. The assembled surface with a DNA zipper was used to capture a recombinant hepatitis C antigen and determine its volume from solution. In this case, DNA zippers not only enable discrimination between specifications and redundant binding, however, allows local application of antibody detection through its removal of false-positive results due to cross-reactive antibodies and waste binding.

Sustainable technological development has found and indicated a niche in biology the beginning of a new revolution. Much attention and progress has been made so far with DNA chips, there is considerable progress in the use of other biomolecules and cells. There are many reviews includes only various aspects and technologies, but provides a shared definition of "biochips".

Biochip and cancer:

Various biochip techniques in cancer research including 1) analysis disease predisposition by using single nucleotide polymorphism (SNP) microarrays, 2) using global gene expression patterns by cDNA microarrays, 3) protein density, functional activity or interaction of proteomic biochips and 4) linked cell types or tissues as well as molecular targets using clinical endpoints in tissue microarrays. One may speculate that individual cancer risks may be anticipated in the future precisely by microarray profiles of multiple SNPs in severe genes.

Metaphase chromosomes have been widely used for comparative genomic hybridization (CGH) for genome-wide screening of genomic anomalies in tumour cells. Chromosome replacement goals of a matrix containing a defined set of nucleic acid target sequences increase resolution and simplify the analysis process, both are a prerequisite for a broad application of CGH as a diagnostic tool.  Although hybridization to whole genomic human DNA below the megabase pair level, complex single-copy DNA fragments become complex due to the complexity, the high probability is constrained by the low probability of precision bonding. High copy multiples contained in tumour cells are scored using small DNA as cosmid. The low-copy-number obtain and reduces are identified accurately by their ratios by usage of chromosome specific DNA library or genomic fragment cloned to 75 kb cloned in PI or PAC vector as targets, as such, improve the resolution determined by chromosomal CGH. THE ratios enter for chromosomal imbalance via matrix CGCH and chromosomal CGH once well discussed. The new matrix CGH protocol provides a basis for the development of automated diagnostic procedures with biochips to meet clinical needs.

Implantable biochip research for department of defence:

Development of an implantable biochip that can relay vital health information when a soldier is injured, injuries have been reported in war or civilian accidents. Biochip on the size of the grain of rice, can measure and relay information such as lactate and glucose levels in a major event bloodshed, whether on the battlefield, at home or on the highway. Other long-term effects of biochip are potential applications, such as monitoring the innovators' vital signs during long-duration space flight, and blood sugar level for diabetic patients.

Biochip systems also have considerable potential as a discovery tool. Current study objective that the development of proteome chips has shown great promise. Proteome chips, which are biochips displays all the proteins released by an organism at a time, providing the ability to screen for new cancer biomarkers provide vaccine targets and treatment targets, as well as a pathway the stages of disease depicted.

9. BIOCHIP MARKET

Over the past ten years, large pharmaceutical companies ("pharma") have seen their research and development costs explode their actual productivity has declined.  Pharmaceutical companies are looking out of their labs for quickly drug products. As a result, pharma companies have become increasingly inventive research and financial partners with several biotechnology companies.

At the same time, pharma companies also want to be customers and partners of biochip companies because these companies’ techniques to help them become more productive faster. The market is being used to accelerate the process and potential of bio-pharmaceutical research Drug discovery and basic academic bio resources.

New business models are being created. The idea is pharmacogenomics and targeted therapies have received positive reception from the government regulators. Roche and Affymetrix are the first companies to receive FDA approval for biochip-basic, molecular diagnostic tests and material systems are assisting with basic academic research as well. Rapid research and advanced industrialization are needed to speed up the process of making drugs. Biotechnology companies such as biotechnology companies provide genomics and proteomics techniques.

10. FUTURE OF BIOCHIPS

Difference in breast cancer and separation drug therapy and disease (Pharmacogenetics) is one of two possible applications of biochips. Gene expression profile in cancer the purity of distinction and cognition allowed, which until now was impossible. Already oncologists will make their treatment decisions based on biochip-based gene expression profile. A separate drug treatment requires extensive comprehensive genetic tests to be completed cytochrome P450 System. Biochip is already firmly available and made possible financially. In addition, biochips in science will play an important role in genetic analysis. If once the pathogenesis of these diseases is understood, the clinical use of biochips will open huge potential for predictive medicine. DNA chips will facilitate diagnostic integration and initiation of treatment, as well as personalized medicines. Application of gold nanoparticles instead of recent years fluorescence dyes and enzyme-conjugates are very common in biochips. For example, Au nanoparticles the labelling method was applied to several DNA detection methods and is a fancy text scheme for gold. The study of nano-particle-based DNA microarrays was based on a ‘’laser-induced scattering around a nanoabsorber “detection of color metrics using nanogold electrodes and gold labels as well as silver stains was also developed. The quality of the probe locations can be analysed using gold nano particle with a positive charge for DNA labelling via electrostatic attraction. Detection spots may also occur detected by a simple personal computer scanner. Gold nanoparticles may accumulate on the glass surface bromine-bromide dissolves in solution. Staining and treating gold particles in a single microarray. The destination can still be used for hybridization with approximately the same efficiency. The technology is a good combination of gene technology and nano technology.

At the same time, a number of scientists from different countries have paid more attention to the application of nanoparticles on biochips and has acquired some new patents for it. This approach governs a standard biochip in microarrays should be a valuable tool for potential and future biomarker discovery. Protein arrays are emerging to follow DNA chips as a potential screening tool. Biochips are a relevant partly already a matter for insurance companies today, much more in the future.

 

11. CONCLUSION

DNA Microarrays are one of the most effective ever developed. A DNA Microarray is a test that allows for the comparison of thousands of genes at once. Microarray technology uses chips with attached DNA sequences as probes for gene expression. Any DNA in the sample that is complementary to a probe sequence will become bound to the chip. Microarray technology is most powerful when it used on species with a sequenced genome. The microarray chip can hold sequence from every gene in the entire genome the expression of every gene can be studied simultaneously. Gene expression data can provide information on the function on the function of previously uncharacterized genes. 

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