Biosensor

A biosensor is a device or a probe that integrates a biological component, such as a whole bacterium or a biological product (e.g., an enzyme or antibody) with an electronic component to yield a measurable signal and detects, records, and transmits information regarding a physiological change or the presence of various chemical or biological materials in the environment. Biosensors come in a variety of sizes and shapes and can detect and measure concentrations of specific bacteria or hazardous chemicals, measure acidity levels (pH).

Biosensors represent a rapidly expanding field, at the present time, with an estimated 60% annual growth rate; the major impetus coming from the health-care industry (e.g. 6% of the western world are diabetic and would benefit from the availability of a rapid, accurate and simple biosensor for glucose) but with some pressure from other areas, such as food quality appraisal and environmental monitoring. Research and development in this field is wide and multidisciplinary, spanning biochemistry, bioreactor science, physical chemistry, electrochemistry, electronics and software engineering. Most of this current endeavour concerns potentiometric and amperometric biosensors and colorimetric paper enzyme strips.

Types

First generation biosensors, where the normal product of the reaction diffuses to the transducer and causes the electrical response, second generation biosensors which involve specific 'mediators' between the reaction and the transducer in order to generate improved response, and third generation biosensors where the reaction itself causes the response and no product or mediator diffusion is directly involved.

Sensing Techniques

Fluorescence, DNA Micro array, SPR Surface plasmon resonance, Impedance spectroscopy, SPM (Scanning probe microscopy, AFM, STM), QCM (Quartz crystal microbalance), SERS (Surface Enhanced Raman Spectroscopy) and Electrochemical methods.

Biosensor Components

Biosensor consists of three parts.

The sensitive biological element (e.g. Tissues, Micro-organisms, Organelles, Cell receptors, Enzymes, Antibodies, Nucleic acids, Synthetic receptors, Sensing organs etc).

The transducer (Acts as an interface, measuring the physical change that occurs with the reaction at the bioreceptor then transforming that energy into measurable electrical output).

Physical transducers (Optical, Electrochemical, Opto-electronic, Piezoelectric, Magnetic Thermal, Mass).

The detector element (Signals from the transducer are passed to a microprocessor where they are amplified and analyzed, the data is then converted to concentration units and transferred to a display or/and data storage device).

Application of Biosensor

Study of biomolecules and their interaction, biospecific interaction analysis (BIA), drug Development, in- home medical diagnosis, environmental field monitoring, scientific crime detection, quality control in small food factory, food Analysis, farm, garden and veterinary analysis, clinical diagnosis and biomedicine, process control such as fermentation control and analysis of food and drink, production and analysis, in microbiological studies of bacterial and viral analysis, pharmaceutical and drug analysis, industrial effluent control, pollution control and monitoring, in mining, industrial and toxic gases detection and military applications.

Nanotechnology-based biosensor

Kansas State University researchers are developing a nanotechnology-based biosensor that may allow early detection of cancer cells and pathogens such as salmonella, E. coli and viruses. The technology, they say, could be useful for in-line monitoring of water quality or food quality at industrial processing sites. Researchers have developed nanotechnology-based biosensors for pathogen detection and cancer biomarker detection. Nanobiosensor technology gives new access to cancer cell's molecular processes. Nanobiosensors can provide significant potential in the early warning and detection of cancer agents such as chemical and biological pollutants, hazardous agents and pathogens.