Bio + Sensor

Biosensors

What are Biosensors?

Any device that

analyzes a biological

compound into a

measurable signal

Composed of a

bioreceptor, transducer,

and an electronic

peripheral

What is a Biosensor?

Current Definition

A sensor that integrates a biological element with a physiochemical

transducer to produce an electronic signal proportional to a single

analyte which is then conveyed to a detector.

Biosensor

Analyte

Sample

handling/

preparation

Detection

Signal

Analysis

Response

1916 First report on immobilization of proteins : adsorption of invertase on activated charcoal

1922 First glass pH electrode

1956 Clark published his definitive paper on the oxygen electrode.

1962 First description of a biosensor: an amperometric enzyme electrodre for glucose (Clark)

1969 Guilbault and Montalvo – First potentiometric biosensor:urease immobilized on an ammonia electrode to detect urea

1970 Bergveld – ion selective Field Effect Transistor (ISFET)

1975 Lubbers and Opitz described a fibre-optic sensor with immobilised indicator to measure carbon dioxide or oxygen.

History of Biosensors

1975 First commercial biosensor (Yellow springs Instruments glucose biosensor)

1975 First microbe based biosensor, First immunosensor

1976 First bedside artificial pancreas (Miles)

1980 First fibre optic pH sensor for in vivo blood gases (Peterson)

1982 First fibre optic-based biosensor for glucose

1983 First surface plasmon resonance (SPR) immunosensor

1984 First mediated amperometric biosensor: ferrocene used with glucose oxidase for glucose detection

History of Biosensors

Key Biosensor Components

Enzyme

Microorganism

Antibodies

Chemoreceptors

Tissue

Organelles

Nucleic acids

Electrochemical

(clark electrode,

ion sel. electrode,

etc)

Optical

(absorbance,

luminescence,

fluorescence, etc)

Piezoelectric

(quartz crystals,

surface acoustic

wave device, etc)

Calorimetric

(thermometric)

Bioreceptor

Transducer

Recordin

g device

Analyte

Detector

Composition of Biosensors

Bioreceptor: Part of device

that interacts with a biological

material to identify and interact

with a target molecule

Transducer: Part of the

device that turns the target

molecule into a measured

signal

Electronic Peripheral: Turns the measured signal into

a graphical user interface (GUI)

utilizing microprocessors

Enzymes, Antibodies, or

nucleic acids.

Piezoelectric, Thermal,

Electrochemical, and

Optical

LED Display

1ST Component: Biological Element

Microorganism

Tissue

Cell

Organelle

Nucleic Acid

Enzyme

Enzyme Component

Receptor

Antibody

The component used to bind the target molecule.

Must be highly specific, stable under storage conditions, and immobilized.

2ND Component: Physiochemical 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.

3RD Component: Detector

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.

www.modernmike.com

WORKING PRINCIPLE

Analyte diffuses from the solution to the surface of the Biosensor.

Analyte reacts specifically & efficiently with the Biological Component of the Biosensor.

This reaction changes the physicochemical properties of the Transducer surface.

This leads to a change in the optical/electronic properties of the Transducer Surface.

The change in the optical/electronic properties is measured/converted into electrical signal, which is detected.

BASIC CHARACTERESTICS

LINEARITY: Linearity of the sensor should be high for the detection of high substrate concentration.

SENSITIVITY: Value of the electrode response per substrate concentration.

SELECTIVITY: Chemicals Interference must be minimized for obtaining the correct result.

RESPONSE TIME: Time necessary for having 95% of the response.

RECOVERY TIME: Time before biosensor is ready to analyze the next sample; should not be more than a few minutes.

WORKING LIFETIME: Determined by instability of the biological material; vary from a few days to few months; Exactech glucose biosensor is usable for over 1 year.

Types of Biosensors

1. Calorimetric Biosensor

2. Potentiometric Biosensor

3. Amperometric Biosensor

4. Optical Biosensor

5. Piezo-electric Biosensor

Piezo-Electric Biosensors

Piezo-electric devices use gold to detect the specific angle

at which electron waves are emitted when the substance is

exposed to laser light or crystals, such as quartz, which

vibrate under the influence of an electric field.

The change in frequency is proportional to the mass of

absorbed material.

Electrochemical Biosensors

For applied current: Movement of e- in redox

reactions detected when a potential is applied

between two electrodes.

Potentiometric Biosensor

For voltage: Change in distribution of charge is detected

using ion-selective electrodes, such as pH-meters.

Optical Biosensors

•Colorimetric for color

Measure change in light adsorption

•Photometric for light intensity

Photon output for a luminescent or fluorescent

process can be detected with photomultiplier

tubes or photodiode systems.

Calorimetric Biosensors

If the enzyme catalyzed reaction is exothermic,

two thermistors may be used to measure the

difference in resistance between reactant and

product and, hence, the analyte concentration.

An Example:

Electrochemical DNA Biosensor

Steps involved in electrochemical DNA

hybridization biosensors:

Formation of the DNA recognition layer

Actual hybridization event

Transformation of the hybridization event

into an electrical signal

Motivated by the application to clinical diagnosis and

genome mutation detection

Types DNA Biosensors

Electrodes

Chips

Crystals

DNA biosensor

DNA BIOSENSOR

Food Analysis

Study of biomolecules and their interaction

Drug Development

Crime detection

Medical diagnosis (both clinical and laboratory use)

Environmental field monitoring

Quality control

Industrial Process Control

Detection systems for biological warfare agents

Manufacturing of pharmaceuticals and replacement

organs

Application of Biosensor

Current Applications and Areas of

Improvement

Current Applications

Lab-on-a-chip

Pollutant Control

Patient Diagnosis

Detection of harmful

pathogens, bacteria,

toxic compounds

Future

Disposable

Low Cost

Increased Sensitivity

Improved

Microprocessors

Multipurpose

Environmental friendly

ADVANTAGES

Highly Specific.

Linear response, Tiny & Biocompatible.

Easy to Use, Durable.

Require only Small Sample Volume.

Rapid, Accurate, Stable & Sterilizable.

Reusable

Reliable web sites for further reading

1- Oak Ridge National Laboratory (ORNL)

http://web.ornl.gov/info/ornlreview/rev29_3/text/biosens

.htm

End of the Class Lectures

Thank you for your enthusiasm

and interest to my class.

Good Luck in your final exams!!!

Biomimetics - term coined by Otto H.

Schmitt in 1969 to describe the idea of

imitating and learning from biology.

Biomimetic

BIOMIMETICS DEFINED

BIOMIMETICS: Application of biological mechanisms to

engineered systems

Artificial neural networks

for pattern matching in

the presence of noise and

uncertainty

Fabrication of molecularly

imprinted polymers –

“plastic antibodies”

Robot “geckos” that can

climb, insects that can fly

Taking hints from nature:

How does nature solve everyday problems

Can we implement nature’s solutions?

The concept of taking ideas from nature to

implement in another technology

The goal of the Biomimetic

The goal of the Biomimetic Millisystems Lab is to

harness features of animal manipulation, locomotion,

sensing, actuation, mechanics, dynamics, and control

strategies to radically improve millirobot capabilities.

Research in the lab ranges from fundamental

understanding of mechanical principles to novel

fabrication techniques to system integration of

autonomous millirobots. The lab works closely with

biologists to develop models of function which can be

tested on engineered and natural systems. The lab's

current research is centered on all-terrain crawling using

nanostructured adhesives and bioinspired flight.

http://robotics.eecs.berkeley.edu/~ronf/Biomimetics.html

Materials & Mechanisms

Advanced Materials, Functional Materials,

Smart Materials, Intelligent Materials !!

Conscious Materials ??!!!

Lotus effect: Self-clean water

repellent surfaces:

Structural colors:

Photonic Crystals

Bio-Adhesion:

nano-

velcro;

Geckel

glue

Low temp

ceramics

Ceetah-inspired quadrupeds

http://biomimetics.mit.edu/

Biotensegrity Structure

http://biomimetics.mit.edu/

The synergetic arrangement of bones and tendons of biological

system inspires a design principle that allows light, robust leg

structure for high speed running.

Micro and nanofiber structures are designed to provide high friction

and adhesive forces through mechanical control of surface

interactions.

http://robotics.eecs.berkeley.edu/

Biologically Inspired Synthetic Gecko Adhesives

Gecko feet: biology

Millions of hairs

called setae

Fiber radius is

nanometer-scale

Adhesion due to

van der Waals

and capillary

forces

Gecko feet: applications

Glue Clues from Geckos

A team of biomedical engineers and materials scientists at Northwestern University have developed a glue inspired by both Geckos and Mussels

They mimic the microscopic hairs of the gecko but add a protein that mimics a protein the mussel uses to adhere to wet surfaces

The result is a post-it note type of adhesive that works on wet or dry surfaces, even after being pulled away and reattached more than 1000 times

What’s the relationship between these two images?

What’s the relationship between these two images?

Velcro and the plant burr that inspired its invention

Velcro

Inspired by the seed

burrs that stuck to his

dog, Swiss engineer

Georges de Mestral

became inspired to

create the hook-and-loop

fastener we call Velcro

Smart-fabric

Pine-cone model

Adapts to changing

temperatures

by opening when warm or

shutting tight if cold

UK Armed Forces Clothing Inspired by

Pine Cones

It is difficult to correctly dress

for the weather and layers can

be cumbersome

UK researchers are

investigating clothing made of

materials that react to

temperature and moisture,

much like pine cones

http://news.nationalgeographic.com/news/2004/10/1013_041013_smart_clothing.html

The goal of this work is to develop high performance ambulating milli-

robots using minimal actuation and passive stabilization mechanisms,

combined with onboard high level control.

Ambulating robots

http://robotics.eecs.berkeley.edu/

Bioinspired sensors and control strategies are being developed for

coordinated flight of multiple ornithopters.

Ornithopter Project

http://robotics.eecs.berkeley.edu/

Shinkansen

Front end modeled after

kingfisher’s beak to

minimize tunnel entry/exit

shockwave

Pantograph supports have

serrations modeled after

owl plumage to reduce

wind noise

Biomimicry: Innovation Inspired by

Nature, J. Benyus, Perrenial NY, 2002

Fishbone Audio Sensor

Tokyo Electron has created the fishbone sensor, a new

type of audio sensor using the inner working of the human

ear as a model

Each of the 24 cantilevers of the fishbone sensor works

like a human ear membrane and picks up individual

frequencies

New Medicine Inspired by Frog Skin

U Penn scientists have developed a potent compound that mimics molecules in frog skin that stab bacteria to death

Bacteria are adapting to conventional antibiotics by modifying their receptors to prevent the antibiotic from taking hold

Countering this new drug would require the bacteria to fully restructure its membrane

Mercedes-Benz Bionic Concept Vehicle

Modeled after the boxfish, it has one of the lowest

Cd’s ever tested (0.19 for the concept car)

http://www.youtube.com/watch?v=R7tIfDS9RkA

The Eastgate Center in Harare, Zimbabwe

Inspired by Termite mound

This structure provide natural air conditioning without energy

consumption

How to Think Like a Biomimic

Determine what you want to “do” (not “make”)

Identify key functions/purpose

Look to see how nature achieves those functions

Go observe nature’s genius and conduct research or

talk to experts to find patterns or principles which

may work for your problem

Brainstorm , design and converse

Refine the design

Class Exercise

Let’s try it!

Reliable web sites for further reading

1- http://robotics.eecs.berkeley.edu/

2- http://biomimetics.mit.edu/