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OPTICAL BIOSENSORS

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Main Components Of An Optical Biosensor (i) a light source (ii) an optical transmission medium (fiber, waveguide, etc.) (iii) ... – PowerPoint PPT presentation

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Title: OPTICAL BIOSENSORS


1
OPTICAL BIOSENSORS
  • A. Erol Fazlioglu

2
Idea Behind Biosensors
  • Medical Diagnostics
  • Chemical and bioterrorism threat.
  • Health danger posed by new strands of microbial
    organisms and spread of infectious diseases.
  • Optical biosensors utilize optical techniques to
    detect and identify chemical or biological
    species.

3
Two Important Components of Biosensing
  • (i) a biorecognition element to detect chemical
    or biological species
  • (ii) a transduction mechanism which converts the
    physical or chemical response of biorecognition
    into an optical signal.

4
Definition and Its Applications-1
  • Biosensors are analytical devices that can detect
    chemical or biological species or a
    microorganism.
  • Applications
  • Clinical diagnostics
  • Drug development
  • Environmental monitoring (air, water, and soil)
  • Food quality control

5
Definition and Its Applications-2
  • A biosensor utilizes a biological recognition
    element that senses the presence of an analyte
    (the specie to be detected) and creates a
    physical or chemical response that is converted
    by a transducer to a signal.

6
Main Components Of An Optical Biosensor
  • (i) a light source
  • (ii) an optical transmission medium (fiber,
    waveguide, etc.)
  • (iii) immobilized biological recognition element
    (enzymes, antibodies or microbes)
  • (iv) optical probes (such as a fluorescent
    marker) for transduction,
  • (v) an optical detection system.

7
Advantages of Optical Biosensors
  • Selectivity and specificity
  • Remote sensing
  • Isolation from electromagnetic interference
  • Fast, real-time measurements 
  • Multiple channels/multiparameters detection
  • Compact design
  • Minimally invasive for in vivo measurements
  • Choice of optical components for biocompatibility
  • Detailed chemical information on analytes

8
Biorecognition
  • The biorecognition elements are biologies such as
    enzymes, antibodies, and even biological cells
    and microorganisms that selectively recognize an
    analyte.
  • Some of the molecular bioreceptors used for
    biorecognition
  • Enzymes
  • Antibodies
  • Lectins
  • Neuroreceptors
  • DNA/PNA

9
Antibody-antigen
10
Optical Transduction
11
Fluorescence Sensing
  • Direct Sensing
  • Indirect Sensing.

12
Optical Geometries of Biosensing
13
Immobilization
  • Physical Methods
  • Ionic Binding
  • Physical Entrapment
  • Chemical Immobilization

14
Fiber-optic Biosensors
Fiber-optic biosensors are widely used because
of their convenient geometry. for example,
longer interaction length and compatibility with
instruments used for in vivo biosensing.
15
Planar Waveguide Biosensors
  • Planar waveguides are media in which the
    propagation of an optical waveguide is confined
    in a dimension comparable to the wavelength of
    light.

16
Evanescent Wave Biosensors
  • These sensors rely on the light that is not
    confined within the waveguide itself, but
    penetrates into the surrounding medium of lower
    refractive index (cladding or air or into a
    surface immobilized biorecognition element) and
    thus senses the chemical environment on the
    surface of the waveguide (or fiber).

17
Interferometric Biosensors
  • Utilizes interference between the light from a
    waveguiding channel with a sensing layer on its
    surface, and that from a reference channel.

18
Surface Plasmon Resonance Biosensors
  • It is an extension of evanescent wave sensing,
    except that a planar waveguide is replaced by a
    metal-dielectric interface.
  • Surface plasmons are electromagnetic waves that
    propagate along the interface between a metal and
    a dielectric material such as organic films.

19
Some Recent Novel Sensing Methods
  • Photonic Crystals Sensors
  • Optical Sensor Array and Integrated Light Source
  • Hybrid Transduction Biosensors
  • Time Domain Sensing
  • Surface-Enhanced Raman Sensors

20
Future Directions
  • Multianalyte Detection
  • New Biorecognition Molecules
  • Fluidics
  • In Vivo Sensors
  • Chemical Identification Biosensors
  • Data Processing, Pattern Recognition, and
    Automation

21
Thanks for your attention!
  • Any questions?
  • A. Erol Fazlioglu
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