A biosensor is an analytical device, used for the detection of an analyte , that combines a biological component with a physicochemical detector
A common example of a commercial biosensor is the blood glucose biosensor, which uses the enzyme glucose oxidase to break blood glucose down.
A device that detects, records, and transmits information regarding a physiological change or process.
a sensor device for detecting and measuring very small quantities or changes in a biochemical or chemical substance, in which a microelectronic component registers reactions related to the substance and translates them into data
There are different types of business based on different principles. However, generally they are categorized as:
According to the mode of interaction business are of two types:
Catalytic biosensor: The interaction of biological material in the biosensor and the annually result in modification of annually into new chemical molecule. The biological material used is mainly enzymes.
Affinity biosensor: Here, upon interaction, the analyte binds to the biomolecule on the biosensor. These are mainly composed of antibodies, nucleic acids etc.
Essential properties of a biosensor:
(i) Specificity: a biosensor should be specific to the analyte which it interact.
(ii) Durability: it should withstand repeated usage.
(iii) Independent nature: It should not be affected by variations in the environment like temperature, pH etc.
(iv) Stability in results: the results produced by interaction should be corresponding to the concentration of analyte.
(v) Ease of use and transport: it should be small in size so that it can be easily carried and used.
Components and mechanism of a biosensor:
A biosensor mainly consists of two parts
(i) a biological part: this constitutes of enzymes antibodies etc., which mainly interacts with the analyte particles and induce a physical change in these particles.
(ii) a transducer part: which collects information from the biological part, converts, amplifies and display them. In order to form a biosensor, the biological particles are immobilized on the transducer surface which acts as a point of contact between the transducer and analyte.
When a biosensor is used to analyse a sample, the biological part specific to the analyte molecules, interacts specifically and efficiently. This produces a physicochemical change of the transducer surface. This change is picked up by the transducer and gets converted into electric signals. These then undergo amplification, interpretation and finally display of these electric units accounting to the amount of analyte present in the sample.
Types of biosensors:
(i) Calorimetric biosensor: some enzyme- analyte reactions are exothermic and releases heat into the sample. This change in temperature is detected by the transducer. The amount of heat generated is proportional to the analyte concentration present and is processed likewise.
(ii) Potentiometric biosensor: an electric potential is produced as a result of interaction which is detected by the transducer
(iii) Amperometric biosensor: analyte when comes in contact with biological material induces a redox reaction. This results in movement of electrons which is picked up by transducer.
(iv) Optical biosensors: in this, a biosensor reacts with analyte to absorb or release light which is identified by the transducer and interpreted.
(v) Acoustic wave biosensors: biological component of biosensor undergoes a biomass change ascertained by transducer.
The advantages of biosensors include accuracy in results, minute detection capability, ease of use, versatile and continuous monitoring available.
A biosensor has a wide range of applications in different fields.
Medicinal Application: biosensors have been used in various diagnostic procedures to determine various tests.
Industrial application: various manufacturing processes can be monitored by biosensors to provide assistance with regard to increase the quality and quantity of product obtained.
Environmental application: it helps in measuring the toxicity of water bodies, microbial contamination of natural resources helping in developing steps towards a cleaner environment.
Military application: it helps to detect explosives, drugs etc., aiding in defence of the people. Another breakthrough in the field of biosensors was the production of a product called ‘smart skin’. It is a kind of biosensor which detects any chemical or biological attack nearby and warns the person using the same.
Drug development: a biosensor called ‘nano sensors’ has been developed which detects and analyse the binding of proteins to its targets which has proved very useful in drug designing. This also helps to monitor certain side effects caused by some medicines.
Bioadhesives are natural polymeric materials that act as adhesives. The term is sometimes used more loosely to describe a glue formed synthetically from biological monomers such as sugars, or to mean a synthetic material designed to adhere to biological tissue. …Source or sample of word “bioadhesive”
Bioadhesives are natural polymeric materials that act as adhesives. The term is sometimes used more loosely to describe a glue formed synthetically from biological monomers such as sugars, or to mean a synthetic material designed to adhere to biological tissue.
Bioadhesives may consist of a variety of substances, but proteins and carbohydrates feature prominently. Proteins such as gelatin and carbohydrates such as starch have been used as general-purpose glues by man for many years
Examples of bioadhesives in nature
Organisms may secrete bioadhesives for use in attachment, construction and obstruction, as well as in predation and defense. Examples include their use for
- colonization of surfaces (e.g. bacteria, algae, fungi, mussels, barnacles)
- tube building by polychaete worms, which live in underwater mounds
- insect egg, larval or pupal attachment to surfaces (vegetation, rocks), and insect mating plugs
- host attachment by blood-feeding ticks
- nest-building by some insects, and also by some fish (e.g. the three-spined stickleback)
- defense by Notaden frogs and by sea cucumbers
- prey capture in spider webs and by velvet worms
Shellac is an early example of a bioadhesive put to practical use. Additional examples now exist, with others in development:
- Commodity wood adhesive based on a bacterial exopolysaccharide
- USB PRF/Soy 2000, a commodity wood adhesive that is 50% soy hydrolysate and excels at finger-jointing green lumber
- Mussel adhesive proteins can assist in attaching cells to plastic surfaces in laboratory cell and tissue culture experiments (see External Links)
- The Notaden frog glue is under development for biomedical uses, e.g. as a surgical glue for orthopedic applications or as a hemostat
- Mucosal drug delivery applications. For example, films of mussel adhesive protein give comparable mucoadhesion to polycarbophil, a synthetic hydrogel used to achieve effective drug delivery at low drug doses. An increased residence time through adhesion to the mucosal surface, such as in the eye or the nose can lead to an improved absorption of the drug.
Several commercial methods of production are being researched:
- direct chemical synthesis, e.g. incorporation of L-DOPA groups in synthetic polymers
- fermentation of transgenic bacteria or yeasts that express bioadhesive protein genes
- farming of natural organisms (small and large) that secrete bioadhesive materials
Iontophoresis, also called electromotive drug administration (EMDA), is a technique using a small electric charge to deliver a medicine or other chemical through the skin It is basically an injection without the needle. The technical description of this process is a non-invasive method of propelling high concentrations of a charged substance, normally a medication or bioactive agent, transdermally by repulsive electromotive force using a small electrical charge applied to an iontophoretic chamber containing a similarly charged active agent and its vehicle. One or two chambers are filled with a solution containing an active ingredient and its solvent, also called the vehicle. The positively charged chamber, called the anode, will repel a positively charged chemical, whereas the negatively charged chamber, called the cathode, will repel a negatively charged chemical into the skin.
the motion of charged particles in a colloid under the influence of an electric field; particles with a positive charge go to the cathode and negative to the anode.
Ionophoresis is a type of:
- natural process, natural action, action, activity (noun) – a process existing in or produced by nature (rather than by the intent of human beings)
Types of ionophoresis:
- immunoelectrophoresis (noun) – electrophoresis to separate antigens and antibodies
- paper electrophoresis, carrier electrophoresis (noun) – electrophoresis carried out on filter paper
ionophoresis is derivationally related to:
- electrophoretic, cataphoretic (adjective) – of or relating to electrophoresis
Iontophoresis is well classified for use in transdermal drug delivery. Unlike transdermal patches, this method relies on active transportation within an electric field. In the presence of an electric field electromigration and electroosmosis are the dominant forces in mass transport. These movements are measured in units of chemical flux, commonly µmol/cm2h.
Reverse iontophoresis is the process by which molecules are removed from within the body for detection. In reverse iontophoresis, the negative charge of the skin at buffered pH causes it to be permselective to cations, causing solvent flow towards the anode. This flow is the dominant force, allowing movement of neutral molecules, including glucose, across the skin. This technology is currently being used in such devices as the GlucoWatch, which allows for blood glucose detection across skin layers using reverse iontophoresis.
Iontophoresis is commonly used by physical therapists for the application of anti-inflammatory medications. Common diagnoses treated with Iontophoresis include plantar fasciitis, bursitis, and some types of hyperhidrosis. In this specific application, the solution chosen is usually tap water, but better results can be obtained using glycopyrronium bromide, a cholinergic inhibitor. Iontophoresis of acetylcholine is used in research as a way to test the health of the endothelium by stimulating endothelium-dependent generation of nitric oxide and subsequent microvascular vasodilation. Acetylcholine is positively charged and, therefore, placed in the anode.
Pilocarpine iontophoresis is often used to stimulate sweat secretion, as part of cystic fibrosis diagnosis