02-08-2014, 12:48 PM
BIOCHIP
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ABSTRACT
A biochip is a collection of miniaturized test sites (microarrays) arranged on a solid substrate that permits many tests to be performed at the same time in order to achieve higher throughput and speed.Like a computer chip that can perform millions of mathematical operations in one second, a biochip can perform thousands of biological reactions, such as decoding genes, in a few seconds.Biochips helped to dramatically accelerate the identification of the estimated 80,000 genes in human DNA, an ongoing world-wide research collaboration known as the Human genome project.Developing a biochip plat-form incorporates electronics for addressing, reading out,
sensing and controlling temperature and, in addition, a handheld analyzer capable of multiparameter identification. The biochip platform can be plugged in a peripheric standard bus of the analyzer device or communicate through a wireless channel. Biochip technology has emerged from the fusion of biotechnology and micro/nanofabrication technology. Biochips enable us to realize revolutionary new bioanalysis systems that can directly manipulate and analyze the micro/nano-scale world of biomolecules, organelles and cells.
INTRODUCTION
A biochip is a collection of miniaturized test sites (microarrays) arranged on a solid substrate
that permits many tests to be performed at the same time in order to achieve higher throughput and speed. Typically, a biochip's surface area is no larger than a fingernail. Like a computer chip that can perform millions of mathematical operations in one second, a biochip can perform thousands of biological reactions, such as decoding genes, in a few seconds.Biochip is a broad term indicating the use of microchip technology in molecular biology and can be defined as arrays of selected biomolecules immobilized on a surface. Biochip will also be used in animal and plant breeding, and in the monitoring of foods andthe environment.Biochip is a small-scale device, analogous to an integrated circuit, constructed of or used to analyze organic molecules associated with living organisms. One type of theoretical biochip is a small device constructed of large organic molecules, such as proteins, and capable of performing the functions (data storage, processing) of an electronic computer. The other type of biochip is a small device capable of performing rapid, small-scale biochemical reactions for the purpose of identifying gene sequences, environmental pollutants, airborne toxins, or other biochemical constituents.
Generation/History
The development of biochips has a long history, starting with early work on the underlying sensor technology.Biochip was originally developed in in 1983 for monitoring fisheries,the rapid technological advances of the biochemistry and semiconductor fields in the 1980s led to the large scale development of biochips in the 1990s. At this time, it became clear that biochips were largely a "platform" technology which consisted of several separate, yet integrated components. Today, a large variety of biochip technologies are either in development or being commercialized. Numerous advancements continue to be made in sensing research that enable new platforms to be developed for new applications. Biochip was invented in 4G generation & the development is still continued, due its various applications. Biochips are also continuing to evolve as a collection of assays that provide a technology platform. One interesting development in this regard is the recent effort to couple so-called representational difference analysis (RDA) with high-throughput DNA array analysis. The RDA technology allows the comparison of cDNA from two separate tissue samples simultaneously.It is important to realize that a biochip is not a single product, but rather a family of products that form a technology platform. Many developments over the past two decades have contributed to its evolution.In a sense, the very concept of a biochip was made possible by the work of Fred Sanger and Walter Gilbert, who were awarded a Nobel Prize in 1980 for their pioneering DNA sequencing approach that is widely used today. DNA sequencing chemistry in combination with electric current, as well as micropore agarose gels, laid the foundation for considering miniaturizing molecular assays
How does a biochip work?
The "chip contains a 10 character alphanumeric identification code that is never duplicated. when a scanner is passed over the chip, the scanner emits a 'beep' and your ... number flashes in the scanner's digital display." Biochips concentrate thousands of different genetic tests on a surface area of just a few square centimetres so that they can be analysed by computer within a very short space of time. On the one hand this makes the individual genetic tests much cheaper and on the other hand, thanks to the capacity, many more tests can be carried out.
Biochips concentrate thousands of different genetic tests on a surface area of just afew square centimetres so that they can be analysed by computer within a very shortspace of time. On the one hand this makes the individual genetic tests much cheaperand on the other hand, many more tests can be carried out.Affymetrix invented the “high-density microarray” in 1989 and has been selling thisassay since 1994 under the name of GeneChip® (figure 1). In this context,microarray means that the genetic tests are organised (arrayed) inmicrometrespacing(micro).As it was not previously possible to go below the millimetre range,the description “high density” is certainly justified. Experiments (e.g. measurement ofgene activity or sequencing to demonstrate mutations and polymorphisms) that couldpreviously only be done individually, one after the other, can now be carried out inlarge numbers at the same time and in a highly automated manner.
The "chip contains a 10 character alphanumeric identification code that is never duplicated. when a scanner is passed over the chip, the scanner emits a 'beep' and your ... number flashes in the scanner's digital display." Biochips concentrate thousands of different genetic tests on a surface area of just a few square centimetres so that they can be analysed by computer within a very short space of time. On the one hand this makes the individual genetic tests much cheaper and on the other hand, thanks to the capacity, many more tests can be carried out.
Biochips concentrate thousands of different genetic tests on a surface area of just afew square centimetres so that they can be analysed by computer within a very shortspace of time. On the one hand this makes the individual genetic tests much cheaperand on the other hand, many more tests can be carried out.Affymetrix invented the “high-density microarray” in 1989 and has been selling thisassay since 1994 under the name of GeneChip® (figure 1). In this context,microarray means that the genetic tests are organised (arrayed) inmicrometrespacing(micro).As it was not previously possible to go below the millimetre range,the description “high density” is certainly justified. Experiments (e.g. measurement ofgene activity or sequencing to demonstrate mutations and polymorphisms) that couldpreviously only be done individually, one after the other, can now be carried out inlarge numbers at the same time and in a highly automated manner.
The "chip contains a 10 character alphanumeric identification code that is never duplicated. when a scanner is passed over the chip, the scanner emits a 'beep' and your ... number flashes in the scanner's digital display." Biochips concentrate thousands of different genetic tests on a surface area of just a few square centimetres so that they can be analysed by computer within a very short space of time. On the one hand this makes the individual genetic tests much cheaper and on the other hand, thanks to the capacity, many more tests can be carried out.
Biochips concentrate thousands of different genetic tests on a surface area of just afew square centimetres so that they can be analysed by computer within a very shortspace of time. On the one hand this makes the individual genetic tests much cheaperand on the other hand, many more tests can be carried out.Affymetrix invented the “high-density microarray” in 1989 and has been selling thisassay since 1994 under the name of GeneChip® (figure 1). In this context,microarray means that the genetic tests are organised (arrayed) inmicrometrespacing(micro).As it was not previously possible to go below the millimetre range,the description “high density” is certainly justified. Experiments (e.g. measurement ofgene activity or sequencing to demonstrate mutations and polymorphisms) that couldpreviously only be done individually, one after the other, can now be carried out inlarge numbers at the same time and in a highly automated manner.
Biochip Architecture
The biochip implant system consists of two components; a transponder and a reader or scanner. The transponder is the actual biochip implant. The biochip system is a radio frequency identification (RFID) system, using low-frequency radio signals to communicate between the biochip and reader. The reading range or activation range, between reader and biochip is small, normally between 2 and 12 inches.
Human interface to Biochip
Biochips provide interfaces between living systems and electro-mechanical and computational devices. These chips may be used in such varied applications as artificial sensors, prosthesis, portable/disposable laboratories or even as implantable devices to enhance human life. Biochips promise dramatic changes in future medical science and human life in general. With the advances of bio and nano technologies two strong paradigms of integrated electronic and life are emerging. Biosensor chips can provide the construction of sophisticated human sensing systems such as nose and ears. The second paradigm is chips for sensing biology that will provide for interactions with living bodies and build new diagnosis tools (such as diabetes glucose meters) or new medicines (such as a bio-assay chip). A tiny microchip, the size of a grain of rice, is simply placed under the skin. It is so designed as to be injected simultaneously with a vaccination or alone."
The biochip is inserted into the subject with a hypodermic syringe. Injection is safe and simple, comparable to common vaccines. Anesthesia is not required nor recommended. In dogs and cats, the biochip is usually injected behind the neck between the shoulder blades. Trovan, Ltd., markets an implant, featuring a patented "zip quill", which you simply press in, no syringe is needed. According to AVID "Once implanted, the identity tag is virtually impossible to retrieve. . . The number can never be altered."
First Implant of Biochip
On May 10 2002, three members of a family in Florida ("medical pioneers," according to a fawning report on the CBS Evening News) became the first people to receive the implants. Each device, made of silicon and called a VeriChip™, is a small radio transmitter about the size of a piece of rice that is injected under a person's skin. It transmits a unique personal ID number whenever it is within a few feet of a special receiver unit. VeriChip's maker describes it as "a miniaturized, implantable, radio frequency identification device (RFID) that can be used in a variety of security, emergency and healthcare applications.
ADVANTAGES & DISADVANTAGES
The ability to detect multiple viral agents in parallel e.g. differential diagnosis of agents from other diseases that cause similar clinical symptoms, or the recognition of complex mixtures of agents. .Clarification of syndromes of unknown aetiology .Increase speed of diagnosis of unknown pathogens ("future proofed" surveillance tools).
.Viral typing (AIV, FMDV, Rabies)
.Drive policy for diagnostics and disease control.
.Epidemiological tracing
.Interagency collaboration. The consortium consists of National, EU and OIE referencelaboratories and has access to real sample material from a wide selection of hosts and viruses
CONCLUSION
Biochips are fast, accurate, miniaturized, and can be expected to become economically advantageous attributes that make them analogous to a computer chip. One expects to see an accelerated trend of ultraminiaturization, perhaps involving entirely novel media, and an increased ability to analyze not only genetic material but also other types of biologic molecules. One expects, too, an eventual harmonization of technologies, so that dominant fabrication strategies will emerge, at least for certain types of applications, including a favored format for genetic analysis and another for antibodies and other proteins. Since the potential applications are vast, both for research and for clinical use, the potential markets for biochips will be huge, a powerful driving force for their continued development .