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Nanobiosensors. Sara Huefner November 6, 2006. Outline. Biosensor Background What is a Biosensor? Components of a Biosensor Principles of Detection Biosensors on the Nanoscale Current Research Potential Applications Conclusion. What is a Biosensor?.

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Sara Huefner

November 6, 2006

  • Biosensor Background
    • What is a Biosensor?
    • Components of a Biosensor
    • Principles of Detection
  • Biosensors on the Nanoscale
    • Current Research
    • Potential Applications
  • Conclusion
what is a biosensor
What is a Biosensor?

“Biosensor” once refered to any device which responds to chemical species in biological samples or using biological components.

current definition for biosensors
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.

components of a biosensor
Components of a Biosensor


1 st component biological element
1ST Component: Biological Element

The component used to bind the target molecule.

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





Nucleic Acid


Enzyme Component



2 nd component physiochemical transducer
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.

3 rd component detector
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.

principles of detection
Principles of Detection


  • measures change in mass
  • measures change in electric distribution
  • measures change in light intensity
  • measures change in heat




principles of detection10

Principles of Detection

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.

Piezo-Electric Biosensors

Others use gold to detect the specific angle at which electron waves (surface plasmons) are emitted when the substance is exposed to laser light.

The change in frequency is proportional to the mass of absorbed material.

principles of detection11

Principles of Detection

  • 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

Electrochemical Biosensors

principles of detection12

Principles of Detection

  • 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.

Optical Biosensors

principles of detection13

Principles of Detection

  • 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.

Calorimetric Biosensors

biosensors on the nanoscale

Biosensors on the Nanoscale

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."

Current Research

biosensors on the nanoscale15

Biosensors on the Nanoscale

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.

Current Research

biosensors on the nanoscale16

Biosensors on the Nanoscale

Nanosphere lithography (NSL) derived triangular Ag nanoparticles were used to detect streptavidin down to one picomolar concentrations.

Current Research

biosensors on the nanoscale17

Biosensors on the Nanoscale

The School of Biomedical Engineering has developed an anti-body based piezoelectric nanobiosensor to be used for anthrax,HIV hepatitis detection.

Current Research

potential applications
Potential Applications
  • Clinical diagnostics
  • Food and agricultural processes
  • Environmental (air, soil, and water) monitoring
  • Detection of warfare agents.


The possibilities are endless!