BTY100-Lec# 2.2 BIOSENSORS Created By: Soumya Srivastava

Outline Biosensors: Basic Concept WorkingPrinciple Types Examples

What are Biosensors??? SENSORS..???

SENSORS A sensor is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an (today mostly electronic) instrument. Any Examples in your surrounding???? A piezoelectric sensor is a device that uses the piezoelectric effect, to measure changes in pressure, acceleration, strain or force by converting them to an electrical charge. The prefix piezo- is Greek for 'press' or 'squeeze'. Ref: logos.co Ref: en.clipart-fr.com Ref: http://eofdreams.com Ref: javla.com Button on Lift-Tactile Sensors Touch Screen Mobile Phones Peizo-electric sensor Thermometer-Temperature Sensor

But Still......What are Biosensors??? BIOLOGY + SENSORS??

Professor Leland C Clark Jnr Bio Sensors A biosensor is an analytical device which converts a biological response into an electrical signal. Any device that uses specific biochemical reactions to detect chemical compounds in biological samples. Father of Biosensors: EUREKA!!! Ref: www.nae.edu Professor Leland C Clark Jnr 1918–2005

Characteristics of a Biosensor Selectivity: Selectivity means that sensor detects a certain analyte and does not react with added mixtures and contaminants. Precision: is the degree to which repeated measurements under unchanged conditions show the same results. Signal stability : signal drift under constant conditions, which causes an error in measured concentration. Sensitivity (detection limit): the minimal amount (or concentration) of analyte that can be detected. Working range : range of analyte concentrations in which the sensor can operate. Regeneration time : time required to return the sensor to working state after interaction with the sample.

Working Principle : Ref: Biosensor Research Centre Biosensors are based on the specific interactions between biological molecules.

Specific Interactions???? Enzyme and substrate Antigen and Antibody Dye and Ligand Sugar and Lectin

Elements of a Biosensor Ref: www.sirebi.org/open/Intro_Biosensing.pdf

A biosensor is a device composed of two main elements: A bioreceptor that is an immobilized sensitive biological element (e.g. enzyme, DNA probe, antibody) recognizing the analyte (e.g. enzyme substrate, complementary DNA, antigen). 2. A transducer is used to convert (bio)chemical signal resulting from the interaction of the analyte with the bio-receptor into an electronic one.

3.An Electronic Amplifier is an electronic device that increases the power of a signal. 4. A Data processing system is a combination of machines that for a set of inputs produces a defined set of outputs. The inputs and outputs are interpreted as data, facts, information, ... depending on the interpreter's relation to the system.

So overall the components collaborate in the following manner : Quickyak: Parts of a BIOSENSOR: Bioreceptor Transducer Amplifier Data Processing System

Working of Biosensor

Example of an enzyme based Biosensor Blood Glucose Biosensor: It is very often used to measure the glucose concentration in blood. Its applicable for diabetes patients for monitoring the blood glucose level.

Working: The basic concept of the glucose biosensor is based on the fact that the immobilized GOx (Glucose oxidase-an enzyme) catalyzes the oxidation of β-D-glucose by molecular oxygen producing gluconic acid and hydrogen peroxide . The enzyme is re-oxidized with an excess of a mediator . The mediator is re-oxidized by a reaction at the electrode and a current is created. The charge passing the electrode is proportional to glucose level. Quickyak: Examples of other biosensors may be given

Types of Biosensors Biosensors are usually classified into various groups: a) On the basis of type of transducer employed:

b) On the kind of bio recognition element utilized (antibody, enzymes, nucleic acids, and whole cells). Enzyme Electrode Enzymes Enzymes are immobilised on the surface of an electrode Current is generated when enzyme catalyses Immunosensor Antibodies Detects change in mass when antibody binds to antigen DNA Sensor Use of DNA probe Microbial Sensor Microbial Cells

Applications The application of biosensor areas are following: Clinical, diagnostics and medical applications. Process control Bioreactors Quality control Agriculture and veterinary medicine Bacterial and viral diagnostics Control of industrial waste water Mining Military defence industry. Environmental control and monitoring

Advantages and Disadvantages They can measure non-polar molecules that do not respond to most measurement devices. Rapid and continuous control is possible with biosensors Biosensors are specific due to the immobilized system used in them. Response time is short (typically less than a minute) and Practical Disadvantages Heat sterilization is not possible because of denaturation of biological material. Stability of biological material depends on the natural properties of the molecule that can be denatured under environmental conditions. The cells in the biosensor can become intoxicated by other molecules that are capable of diffusing through the membrane.

Recent Advances Technologies Already Available in Market Zeo Designed to analyze and improve sleep In 2011, the widget maker Zeo introduced a mobile version to its Sleep Manager product line. By wearing a special headband, with sensors to measure electrical current, the Zeo could track different phases of sleep, such as Light, Deep and REM sleep, in addition to awake time. This data was then sent to an iPhone, iPod, or Android phone, and could be automatically uploaded to a personal and private online sleep database. This data along with some analytical tools could then be used to help improve your sleep and health. Zeo tells you how you really sleep, and helps you find ways to improve your sleep Accurately measure your sleep quality and sleep quanity at home Discover factors that are stealing your Deep, REM & total sleep Analyze your sleep patterns using online tools and journals Add sleep coaching for a customized sleep improvement program tailored just for you

i-STAT Portable Clinical Analyzer Handheld blood analyzer system BODYBUGG Personal calorie management system Home Blood Glucose Monitors ACCUTRANS - Disposable blood pressure transducer

Future Endeavours Tattoo Biosensors: Quickyak: Chip Sensors: It allows one to measure pesticide content on food produce, water and soil. Ring Sensor: It allows one to continuously monitor heart rate and oxygen saturation. The device is shaped like a ring. Smart Shirt: This technology has been used to integrate sensors for monitoring the vital signs like temperature, heart rate and respiration rate. Tattoo Biosensors: Biosensor tattoos were developed to monitor sweat and lactate levels as indicators of excessive physical activity Quickyak: These products are still not commercialized

Ring Sensor Advantages Disadvantages Wireless supervision of people during hazardous operations. In an overcrowded emergency department. Chronic surveillance of abnormal heart failure. In cardio-vascular disease for monitoring the hyper tension. Advantages Continuous monitoring. Easy to use. Reducing hospitalization fee Disadvantages Initial cost is high. Limited number of physiological parameters can be monitored.

Smart Shirts Also known as GTWM i.e. Georgia Tech Wearable Motherboard. This GTWM (smart shirt) provides an extremely versatile framework for the incorporation of sensing, monitoring and information processing devices. It uses optical fibers to detect bullet wounds and special sensors and interconnects to monitor the body vital signs during combat conditions. It is used to integrate sensors for monitoring the vital signs like temperature, heart rate and respiration rate. Fig- Architechture of Smart Shirt[2]

Working of Smart Shirt (cont..)

A Day may come… Quickyak: Is this a biosensors Soon humans may also have a unique bar code Quickyak: Is this a biosensors Could they act as Biosensors??

Next Class: Nanobiotechnology