Biosensors

Biosensors

Biosensors

Hojjat Adeli is at the Department of Civil and Environmental Engineering, and Geodetic Science, The Ohio State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, Ohio 43210, USA.

Keywords: Biosensor, Medicine, Epilepsy

Biosensors and biometrics are rapidly becoming one of the most expanding areas of research. Biosensors are devices that detect, record, and transmit information about biological, physiological, and chemical changes. The main components of a biosensor are a biological recognition element, a transducer which converts the biorecognition element into a measurable signal, and a signal and data processing system (Sharma and Rogers, 1994). Biological elements recognized by biosensors can be antibodies, antigens, cells (such as microbial cells), enzymes, receptors, sensing organs, and tissues. Physical transducers include electrochemical, mass, optical, opto-electronic, and piezoelectric. Although researchers have already made a number of impressive inroads in the creation and use of biosensors as noted by some of the articles published in this special issue few have been widely commercialized. The number and types of biosensors as well as their commercialization, however, are expected to grow rapidly in the coming decades as noted by a large variety in their sizes and shapes.

Biosensors have potentials to be used in a variety of applications such as:

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  clinical detection and medical diagnosis,

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  health management,

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  pharmaceutical (for example, to speed up new drug trials),

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  microbiology and contamination control,

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  environmental pollution control and monitoring,

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  agriculture (for example, crop diseases and pesticides),

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  veterinary analysis,

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  food and drink production (for example, for rapid detection of pathogenic organisms such as E. coli),

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  industrial process,

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  military, and

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  protection against biological terror.

One of the first biosensors developed by researchers at Oak Ridge National Laboratory (ORNL), dubbed immunosensor, used an antibody (a protein substance produced in the blood or tissues in response to a specific antigen) attached to the end of an optical fiber to detect cancer-causing agents in groundwater. Researchers at ORNL have demonstrated that a 2×2 mm silicon chip attached to the skin can measure body temperature and send the data via radio frequency to a remote monitor (Jacobson, 2003). Researchers are now working on biosensors for detecting the presence of biological and chemical warfare agents for applications in the military and war against terrorism. Recent advances in biosensor technology include DNA sensors, quartz-based piezoelectric oscillators, and surface acoustic wave detectors (Dong and Chen, 2002).

Biosensors will be a key biotechnology element in revolutionary transformation of the medicine in the coming decades. Medical telesensors will measure physiological data such as body temperature, blood pressure, pulse rate, and oxygen level and send them via wireless transmission and global positioning satellite systems to remote intelligent monitors. The immediate application of medical telesensors will be to manage patients requiring intensive care or with life-threatening diseases. The biosensor technology in tandem with advanced signal processing technologies will provide early diagnosis of diseases and maximize the benefits of medical treatments. Eventually, the health of an entire community (or an army of soldiers) can be monitored centrally at the local community hospital (or behind the front away from the war zone).

The author and his associates are learning about the brains of epileptics by investigating epileptiform discharges in recorded brain waves or electroencephalographs (EEGs). They are creating computational models for automatic detection of epileptic discharges that can be used to predict the onset of seizure through adroit integration of three different computing paradigms: chaos theory, neurocomputing, and wavelets (Adeli et al., 2003). A goal of this research is to predict the on-set of seizure in epileptics before it occurs. A biosensor can be implanted in the brain of an epileptic patient to monitor the epileptiform discharges. An implanted micro-device can administer an appropriate dose of medication to control the seizure. This will be a breakthrough in treating epileptic patients. Similar breakthroughs are envisaged in diagnosis and treatment of other diseases from diabetes to cancer and Alzheimer's where biosensors can measure the level of chemical agents in the body or detect abnormalities. For example, a laser fluorescence biosensor can detect when a benign tumor becomes cancerous thus eliminating the need for a surgical biopsy.

Among the emerging trends and promising developments are

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  integrated biosensor and smart signal processing systems,

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  miniaturization and application of nanomaterials in biosensors,

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  use of biosensors in extreme environments, and

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  use of biosensors in food and drink industries (Mello and Kubota, 2002).