Biosensors:Future Technology [Archives:2003/681/Education]
By Shafeeq Mohammed
[email protected]
Years from now a typical doctor visit might not include dull magazines , pharmacy lines and saying “Ahh” , instead , a chip implanted in the body will function as a constant on board doctor , detecting diseases early and delivering drugs straight into the blood stream. Sound like an Orwellian / Asimov hybrid to be seen in an episode of a Jestonic future Space age Cartoon ? Think again . Biosensors could make this scenario a reality before your toddler goes to college.
Why Biosensor ?
Bacteria.,Our invisible friends, our invisible enemies. Some aid our digestion, others destroy our poisons. Still other “bugs” make us sick. Living inside and outside our bodies, natural bacteria are a fact of life. We have learned to live with them and they with us. Soldiers and sailors in action worry that even more dangerous bacteria are lurking in the environment. These are “killer” bacteria—the kind used as weapons. Such biological warfare agents are viewed by many to be as threatening to human life as nuclear weapons. The key to protecting a military unit or community from dangerous bacteria is to detect them before they reach their intended victims. People can then be warned to leave an area or at least wear protective gear. . Bacteria can be detected using “biosensors.”
What is Biosensors ?
A biosensor is a device that detects, records, and transmits information regarding a physiological change or the presence of various chemical or biological materials in the environment. More technically a Biosensor will be defined as a “ Compact analytical device incorporating a biological or biologically –derived sensing element either integrated within or intimately associated with a physicochemical transducer.” The usual aim of a biosensor is to produce either discrete or continuous digital electronic signal which are proportional to signal analyte or a related group of analytes.
Biosensors, which come in a large variety of sizes and shapes, are used to monitor changes in environmental conditions. They can detect and measure concentrations of specific bacteria or hazardous chemicals; they can measure acidity levels (pH).
Bioreporters
Genetically engineered bacteria can also be useful because of their ability to “tattle” on the environment Such Bacteria give off a detectable signal, such as light, in the presence of a specific pollutant they like to eat. They may glow in the presence of toluene, a hazardous compound found in gasoline and other petroleum products. They can indicate whether an underground fuel tank is leaking or whether the site of an oil spill has b een cleaned up effectively. These informer bacteria are called Bioreporters
Biosensors in Medical and Other environmental Probs
Biosensors are already thriving in the medical field. From 1990’s biosensors have been used as immunosensors to destroy or weaken invading bacteria and neutralize organic poisons in the human body. External biosensors are used in emergency room as a point-of- care diagnostic units – such as I-Stat’s ( Manufacturing company ) “ LABS –on a CHIP “ , which can reveal almost immediately whether a patient is in cardiac arrest by testing blood chemistry .
Other companies are developing implantable biosensors that track blood glucose levels and deliver insulin. Microchip ( company ) is testing a chip implant that offers long term , time-controlled drug delivery . Their next step is a manually wirelessly controlled biosensors that detects and treats an acute condition and then a Biosensor that will approximate an artificial organ. It will sense a condition and respond automatically without user intervention.
Medical telesensors
This “medical telesensor” chip on a fingertip can measure and transmit body temperature.
.An array of chips attached to your body may provide additional information on blood pressure, oxygen level, pulse rate , breathing ( chest expansion ) , Knee bending during physical rehabilitation and foot pressure distribution. Biosensors are also used to detect the state of aging diseases like ‘diabetes’ and Alzheimer. This is accomplished by sensing the metal Ion concentrations in the body.
These chips may be attached at various points on a soldier using a nonirritating adhesive like that used in waterproof band-aids. These medical telesensors would send physiological data by wireless transmission to an intelligent monitor on another soldier’s helmet. The monitor could alert medics if the data showed that the soldier’s condition fit one of five levels of trauma. The monitor also would receive and transmit global satellite positioning data to help medics locate the wounded soldier
Wireless monitors attached to the skin could provide valuable information on the physiological condition of Intensive Care Patient’s in Hospital , high –risk out patients , babies at risk of suffering sudden infant death syndrome and Police and fire fighting personel in hazardous situations.
Detecting Cancer And Health Abnormalities
Another type of biosensor uses sophisticated technology to detect a specific trait or abnormality in a living organism . Thompson Cancer Survival Center of Knoxville,( USA ) have developed a new laser technique for nonsurgically determining whether tumors in the esophagus are cancerous or benign.
This laser-based fluorescence method has eliminated the need for biopsy, reducing pain and recovery time for patients.
In DNA Sequence Analysis
DNA can be used to identify organisms ranging from humans to bacteria and viruses. The identification consists of reading the sequence of the DNA letters (A, G, C, and T). By knowing the DNA sequence ,a doctor can determine whether you are a carrier of a disease gene known to exist in your family, wheth er blood at a crime scene was that of the arrested suspect, or whether a biowarfare bacterium was descending on a battlefield. Studies in this area is very fast and less expensive now with Biosensors. Success of the DNA sequence would revolutionize Bio-Medical Science
Applications of Biosensors are limited to our imagination.
In view of the space constraint only a few are listed below
• Environmental Monitoring . ( eg : Detect ‘Anthrax’ etc )
• Food And Drink
• Process Industries ( eg: Petroleum and Chemical refineries )
• Defense and Security
• Anthropometry – to measure human body surface .
Conclusion.
The indication is that analytical chemistry and sensor technology in particular , could follow the same trend as microelectronics. As chemical analysis becomes simpler and more widely available , we can expect to see a proliferation of uses in conjunction with microprocessors and telecommunication equipment. Equipment capable of monitoring data as well as processing it could find wide application in monitoring health , food we eat and our environment.
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