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BioChips: A Hospital in a shoebox

Over the past few years, increasing fuss has centred round the notion of biochips, and how they are fostering a new era for medicine. But what exactly is a biochip?

A biochip is a computer chip, that is a mix of circuits for electrical signals, and tiny canals for fluid, usually blood.

There are many different definitions for a biochip. Some class biochips as those RFID chips injected into humans and animals. A few consider a petridish full of lab-grown rat brain cells hooked to a pc as a biochip. Others regard prosthetic interface chips as biochips, whilst still others lab-on-a-chips to be biochips. So who is right?

Well, all of them. The standard definition for a biochip is a chip that has both inorganic, and organic components. However, the original meaning was a lab-on-a-chip, and is the one covered here.

Biochips came about through the ongoing push of technology for miniaturisation and automation. They allow biotechnologists to begin packing their traditionally bulky sensing tools into smaller and smaller spaces, using biochips as miniature, mass production laboratories, each capable of or thousands of simultaneous biochemical reactions.

They are basically the pack mules of brute-force diagnosis.


New mobile biochip lab checks for 100 different arthritis pathogens in a shoebox-sized machine - there and then.

 

Current Biochips

Whilst biochip science is still fairly primitive, a number of very potent uses are already available, or under review, for both health care, and terrorism security.

Arthritis

The cause of arthritis can often be sought way back in the past. Was it triggered by a bacterium? If so, by which of the at least eight known pathogens - Chlamydia or Salmonella, Borrelia or Campylobacter? Is there a virus involved, for instance Parvovirus B19? Or is the joint inflammation not due to an infection at all?

Usually it takes weeks of laboratory investigations to determine the exact cause of the complaint - and during this time the patient is often given the wrong treatment. A mobile laboratory system to fix this bottleneck has recently been developed in Germany.

Housed in a case that is not much bigger than a shoe-box and will easily find room in any doctor's practice, it consists primarily of a biochip, a black plastic wafer the size of a thumbnail, on which a hundred different antigen dots are printed. Each one of these 500-micrometer dots holds immobilised antigens of a possible arthritis pathogen.

The entire arthritis test can be carried out with only about half a millilitre of blood serum. The blood serum contains all the antibodies that the person's immune system has ever produced. If an antibody from the blood finds its "own" antigen on the chip, it reacts accordingly.

Fluorescent tagging makes this reaction visible. A reading device registers the fluorescent dots and identifies the respective antigen. If the test fails to produce a response, the cause is not an infection at all, but degeneration of the joint.

The biochip is housed in a cartridge the size of a credit card, in which all steps of the reaction take place successively. Microchannels and fluid distributors direct the chemicals to the exact spot where they are needed. The lab system is fast and efficient: it can process up to five cartridges from different patients at the same time within the space of only two hours.

Similar shoebox labs are under development for cancer detection, deep vein thrombosis and prenatal screening.

Lab Research

lab-on-a-chip, when combined with impedimetric technology, bioinformatics, optics and wireless communication can create what amounts to a major research laboratory for drug development, or substance testing, that can work in a fraction of the time humans take. This is because each chip can perform thousands of experiments - often tens of thousands - in the same time, and using the same amount of lab space and sample, a human researcher would take to perform one test.

Biochips don't have to accept blood as input. They can just as easily take a sample of fluid with a dissolved drug in it, and test it simultaneously against thousands, or tens of thousands of other drugs and watch for a negative reaction, vastly improving the speed, efficiency, and reliability of clinical trials.

Future Biochips

As biochips evolve into more and more powerful labs, they will be able to identify an ever increasing number of conditions. Combined with gene mapping, and protein sequencing, both of which are evolving at a frantic pace, it will not be many years before biochip labs are available for the home, that can diagnose a wide range of health conditions from a pinprick.

These will be the beginnings of the 'hospital in a home' that true long-term virtual existence immersion requires - to sustain the body in long periods when it is not really used by it's occupant. Biochips will be able to identify the early signs of a condition for the computer to treat, or, more likely, at least at first, transmit to the GP or hospital for treatment advice.

Eventually, biochip systems will likely cut out the majority of minor trips to the doctor, greatly easing GP workloads, and allowing them to concentrate on more serious complaints that blood work cannot help identify.

In security, biochips will become invaluable for testing and identifying unknown substances quickly and cheaply.

In rivers and sewers they will be able to identify pollutants or banned substance disposal on site, and without requiring a human present. Combined with a sensor network, they would swiftly flag up warnings for the health board to investigate.

In short, wherever there are fluids, there is an application for biochips. Biochips are already here, and advancing at a swift pace. The next decade is going to be fun.

References

Rapid diagnosis, VWN News, 23/09/2006
http://www.virtualworldlets.net/Archive/IndividualNews.php?News=1666

biochip - a definition from Whatis.com
http://whatis.techtarget.com/definition/0,,sid9_gci211664,00.html

Polymer-Based Lab-on-a-Chip System Development
http://www.azonano.com/details.asp?ArticleID=1452

Biochip - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Biochip

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