What is a Biosensor?

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In 1967 S.J. Upp Dick, the first biosensor glucose sensor was made. The glucose oxidase was contained in the polyacrylamide colloid, and then the rubber film was fixed on the tip of the diaphragm oxygen electrode, and a glucose sensor was made. Other sensors of their counterfeit are detected when cured filming films such as other enzymes or microorganisms are used. The method of fixed susceptibility film has a direct chemical combination method; a polymer carrier method; a polymer film combination method. The second-generation biosensor (microorganism, immunization, enzyme immunity, and cytoplast sensor) has been developed, developed, and developed third-generation biosensor, and combining the system biotechnology and electronic technology, the field-effect biosensor is opened in the 1990s. Flow control technology, the microfluidic chipset of biosensor is a new technical prospect for drug screening and gene diagnosis. Due to the granule membrane, microbial membrane, antigenic membrane, antibody film to the biological structure of the enzyme membrane, mitochondrial electron transfer system, and the biosensor has a very high selectivity of the biosensor. The disadvantage is that the biological cured film is unstable. The biosensor involves biomass, mainly used for clinical diagnosis and examination, and implementation of monitoring, fermentation industries, food industry, environmental, and robots.

I. Working Principle of Biosensor

A biosensor consists of the sensor signal converter, the biosensor, the optical sensor, the temperature sensor, and the piezoelectric sensor, the second is an electrochemical electrode, semiconductor, photoelectric converter, thermistor, piezoelectric crystal, etc..

A biosensor is identified by molecular identification portions (sensitive elements) and conversion portions (sensors) to identify the target, which is the primary functionality that can be caused by physical or chemical changes. Molecular identification is the basis for the selective measurement of biosensors.

A substance that selects a specific trait in an organism, such as enzymes, antibodies, tissues, and cells. These molecular identification functions can bind to the identification process detected, such as antibodies, antigens, enzymes, and substrate binding. When designing a biosensor, it is very important to select a suitable material to identify the identification of the subject and take into account the characteristics of the complex. Selecting the sensor is another important part of the development of high-quality biosensor based on chemical or physical changes caused by functional material sensitive components. The generation or consumption of light, heat, and chemicals can produce corresponding changes. Based on these changes, we can choose the appropriate optical sensor.

A biosensor is composed of a molecular identification portion (sensitive element) and a conversion portion (transducer):

- The test target is identified in a molecular identification portion, which can cause a primary functional elements of a physical change or chemical change. The molecular identification part is the basis for selective measurement of biosensors.

- Convert the signal of biological activity to the physical or chemical transducer (sensor) of the electrical signal

Various biosensors have a common structure: including one or several associated biologically active materials (biofilms) and physical or chemical transducer (sensors) that can convert the biologically active expression to electrical signals, both combined Together, the re-processing of biological signals with modern microelectronics and automation instrument techniques, constitutes various biosensor analysis devices, instruments, and systems that can be used.

The biosensor achieves the following three functions:

(1) Touch: Extracting the bio-material that exerts a perceived effect, including biological tissue, microorganism, orpatter, enzyme, antibody, antigen, nucleic acid, DNA, etc. Realize the bioterial production, repeated utilization, and reduce detection and cost of detection of biomaterials or biomaterials.

(2) Observe: Continue to the biomaterial and regular information conversion to information that people can understand.

(3) Reaction: Provide information to people through optical, piezoelectric, electrochemical, temperature, electromagnetic, etc., provide a basis for people's decision-making.

II. Types of Biosensor

The sensor of use of immobilized biological components or organisms as the sensitive element is referred to as a biosensor (Biosensor). The biosensor does not specifically refer to sensors in the field of biotechnology, and its application also includes environmental monitoring, health care, and food inspection. The biosensor mainly has three types of classification:

1. Depending on the molecular identification element in the biosensor, the sensitive element can be divided into five categories: enzyme sensors, microbial sensors, cell sensors, tissue sensors, and immunotensor. Obviously, sensitive materials used are enzymes, microbial individuals, or organisms, animal and plant tissues, antigens, and antibodies.

2. According to the transducer of the biological sensor, the signal converter is classified with: a biological electrode sensor, a semiconductor biosensor, a photobiographic, a thermal biological sensor, a piezoelectric crystal biosensor, and the like, and the transducer sequentially is an electrochemical electrode, a semiconductor, and photoelectric conversion. Thermal resistance, piezoelectric crystals, etc.

3. Biological affinity biosensor, metabolic or catalytic biosensor is classified by the interaction of the target to the molecular identification element.

III. Applications of Biosensor

A biosensor is a high-tech that is penetrated from various disciplines such as biological, chemical, physics, medicine, and electronic technology. Because it has good selectivity, high sensitivity, fast analysis speed, low cost, in a complex system, in particular, its highly automated, miniaturized, and integrated characteristics, it has been obtained in recent decades Flour and rapid development.

There is a wide range of application prospects in various departments of the national economy such as food, pharmaceutical, chemical, clinical inspection, biomedical, environmental monitoring. Especially new disciplines such as molecular biology and microelectronics, optoelectronics, microfabrication technology, and nanotechnology, combined with new technologies, are changing traditional medicine, environmental scientific animal and plant. The research and development of biosensors have become a new hotspot in the development of world science and technology, forming an important part of the 21st century emerging high-tech industry, has important strategic significance.

1. Food industry

The application of biosensors in food analysis includes measuring analysis of food ingredients, food additives, harmful toxicities, and food freshness.

In the food industry, glucose content is an important indicator for measuring fruit maturity and storage life. The developed enzyme-electrode biosensor can be used to analyze white wine, apple juice, jam, and glucose in honey. Other sugars, if saccharides, beer, maltose in the malt, have a mature measurement sensor.

Niculescu developed an ampere biosensor for detecting ethanol content in the beverage. Such a biosensor is to burn a protein alcohol dehydrogenase in polyethylene, the ratio of the enzyme and the polymer can affect the performance of the biosensor. In the experiment conducted, the measurement limit of the biosensor to ethanol was 1 nmol / L.

2. Clinical medicine

In clinical medicine, the enzyme electrode is the earliest use of the most applicable sensor, which has been successfully applied to blood sugar, lactic acid, vitamin C, uric acid, urea, glutamic acid, aminotransferase, and other substances. The principle is that the enzyme is mounted on the biosensitive film with the immobilization technique, and the sample contains the corresponding enzyme substance, and the acceptable information material can be reacted, indicating that the electrode response can be converted to the electrical signal change, According to this change, it can determine whether there is a certain substance. Using microbial replacement enzymes with different biological properties, microbial sensors can be made, and microbial sensors used in the clinic have sensors such as glucose, acetic acid, cholesterol. If you select a suitable tissue containing more enzymes, the sensor made of the corresponding enzyme is referred to as a biological electrode sensor. For sensors made of pig kidney, rabbit liver, bovine liver, beets, pumpkins, and cucumber leaves, can be used to detect gust, guanine, hydrogen peroxide, tyrosine, vitamin C, cystine.

The DNA sensor is the most reported in the biosensors. It is used for the clinical diagnosis of DNA sensors. It can help doctors understand the occurrence, development process of disease from DNA, RNA, protein, and their interaction. Timely diagnosis and treatment of diseases. In addition, drug detection is also a highlight of the DNA sensor. BRABEC et al. Utilizes DNA sensors to study the mechanism of action of common platinum anticancer drugs and measure the concentration of such drugs in the blood.

3. Virus detection

Biological sensing techniques can play an important role in virus detection. A new nano-biosensor can detect a variety of different viruses in just 2 to 3 hours.

Traditional test methods may take one to three days to complete, however, this new biosensor uses an increased frequency-converted resonance energy transfer (LRET) for ultra-sensitive virus detection in liquid phase systems.

The technology is designed and easy to operate, and no expensive equipment or professional skills are required. This technique is also designed to identify gene sequences of almost any known target virus. Best, this technology can even be adjusted to identify a variety of influenza viruses on a single test platform.