1) Nanobiosensors integrate biological components with physiochemical transducers to detect analytes. They can detect changes in mass, electricity, light, heat.
2) Current research is developing nanobiosensors using techniques like molecular sheaths on nanotubes, olfactory proteins on nanoelectrodes, and triangular silver nanoparticles.
3) Potential applications of nanobiosensors include clinical diagnostics, food/ag testing, environmental monitoring, and detecting warfare agents.
2. Outline
• Biosensor Background
– What is a Biosensor?
– Components of a Biosensor
– Principles of Detection
• Biosensors on the Nanoscale
– Current Research
– Potential Applications
• Conclusion
3. What is a Biosensor?
“Biosensor” once refered to any device which responds to chemical
species in biological samples or using biological components.
www.wvminesafety.org http://www.gentronix.co.uk/images/newscientist.jpg
4. Current Definition for Biosensors:
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.
www.imec.be/ovinter/static_research/BioHome.shtml
5. Components of a Biosensor
http://www.dddmag.com/images/0409/HTS1_lrg.jpg
Detector
6. 1ST
Component: Biological Element
Microorganism
Tissue
Cell
Organelle
Nucleic Acid
Enzyme
Enzyme Component
Receptor
Antibody
The component used to bind the target molecule.
http://www.chemistry.wustl.edu/~edudev/LabTutorials/HIV/DrugStrategies.html
Must be highly specific, stable under storage conditions, and immobilized.
7. 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.
8. 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
9. Principles of Detection
measures change in mass
measures change in electric distribution
measures change in light intensity
measures change in heat
10. Principles of Detection
Piezo-Electric Biosensors
The change in frequency is proportional to
the mass of absorbed material.
Some piezo-electric devices utilize crystals, such
as quartz, which vibrate under the influence of
an electric field. The frequency of this oscillation
depends on their thickness and cut.
electronics.howstuffworks.com
Others use gold to detect the specific angle
at which electron waves (surface plasmons)
are emitted when the substance is exposed
to laser light.
11. Principles of Detection
Electrochemical Biosensors
•Amperometric for applied current: Movement of e- in redox
reactions detected when a potential is applied between two
electrodes.
•Potentiometric for voltage: Change in distribution of charge is
detected using ion-selective electrodes, such as pH-meters.
•Conductimetric for impedance
http://www.lsbu.ac.uk/biology/enztech/index.html
12. Principles of Detection
Optical Biosensors
•Colorimetric for color: Measure
change in light adsorption as
reactants are converted to
products.
•Photometric for light intensity:
Photon output for a luminescent or
fluorescent process can be
detected with photomultiplier tubes
or photodiode systems.
www.manimo.it/Prodotti/
13. Principles of Detection
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.
www4.tsl.uu.se/~Atlas/DCS/DCSIL/therm.html
14. Biosensors on the Nanoscale
Current Research
Dr. Michael Strano at the University of] Illinois, "We have
developed molecular sheaths around the nanotube that respond
to a particular chemical and modulate the nanotube's optical
properties."
http://www.worldchanging.com/archives/001727.html
15. Biosensors on the Nanoscale
Current Research
SPOT-NOSED Project: A layer of olfactory proteins on a
nanoelectrode could react with low-concentration odorants. This
technology could be used by doctors to diagnose diseases at
earlier stages.
http://www.sciencedaily.com/releases/2006/05/060515095600.htm
16. Biosensors on the Nanoscale
Current Research
Nanosphere lithography (NSL) derived triangular Ag
nanoparticles were used to detect streptavidin down to one
picomolar concentrations.
http://www.chem.northwestern.edu/~vanduyne/pdf/MRS_723_O311-0316_2002.pdf
http://faculty.washington.edu/stenkamp/stefanieweb/hydro.html
17. Biosensors on the Nanoscale
Current Research
The School of Biomedical
Engineering has
developed an anti-body
based piezoelectric
nanobiosensor to be
used for anthrax,HIV
hepatitis detection.
http://www.biomed.drexel.edu/TechPort/Contents/Lec/Overview/Lec_BioSensors.pdf
