self contained integrated device. provide qualitative and semi qualitative analytic information. biological recognition element which in direct spatial contact with element

2. Self contained integrated device
Provide qualitative or semi quantitative analytical
information
Biological recognition element which in direct
spatial contact with transduction element.

3.  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

4. Professor C CLARK JNR
(1918-2005)

5. :

7. :

9.  Calorimetric/Thermal Detection Biosensors
 Optical Biosensors
 Resonant Biosensors
 Piezoelectric Biosensors
 Ion sensitive Biosensors
 Electrochemical Biosensors

10. BASIC :
 Linearity
 Sensitivity
 Selectivity
 Response time

11. In a biosensor, the bio receptor is designed to
interact with the specific ANALYTE of interest to
produce an effect measurable by the transducer.
 High selectivity for the ANALYTE among a matrix
of other chemical or biological components is a key
requirement of the bio receptor .
 While the type of bio molecule used can vary
widely, biosensors can be classified according to
common types bio receptor interactions involving:
antibody /antigen, enzymes / ligands nucleic
acids/DNA, cellular structures/cells, or bio mimetic
materials.

12.  An IMMUNOSENSOR utilizes the very specific
binding affinity of antibodies for a specific
compound or antigen.
 The specific nature of the antibody-antigen
interaction is analogous to a lock and key fit in
that the antigen will only bind to the antibody if
it has the correct conformation

13. The use of antibodies as the bio-recognition component
of biosensors has several drawbacks. They have high
molecular weights and limited stability, contain essential
disulfide bonds and are expensive to produce.
 In one approach to overcome these limitations,
recombinant binding fragments (FAB, FV OR SCFV) or
domains (VH, VHH) of antibodies have been engineered.
In another approach, small protein scaffolds with
favourable biophysical properties have been engineered to
generate artificial families of Antigen Binding Proteins
(Ag BP), capable of specific binding to different target
proteins while retaining the favourable properties of the
parent molecule.

14. The specific binding capabilities and catalytic activity
of enzymes make them popular bio receptors.
ANALYTE recognition is enabled through several possible
mechanisms:
 1) the enzyme converting the ANALYTE into a product that is
sensor-detectable,
 2) detecting enzyme inhibition or activation by the ANALYTE , or
 3) monitoring modification of enzyme properties resulting from
interaction with the ANALYTE .
The main reasons for the common use of enzymes in biosensors
are:
 1)ability to catalyze a large number of reactions;
 2) potential to detect a group of ANALYTES (substrates, products,
inhibitors, and modulators of the catalytic activity

15. An important part in a biosensor is to attach the
biological elements (small
molecules/protein/cells) to the surface of the
sensor (be it metal, polymer or glass).
The simplest way is to FUNCTINALIZE the
surface in order to coat it with the biological
elements.
This can be done by POLYSINE , amino SILANE ,
epoxy SILANE or nitrocellulose in the case of
silicon chips/silica glass. Subsequently, the bound
biological agent may be for example fixed
by layer by layer DEPOSITATION of alternatively
charged polymer coatings.

16. ICS channel open ICS channel closed
The use of ion channels has been shown to offer highly
sensitive detection of target biological molecules . By
embedding the ion channels in supported or tethered
BILAYER membranes (t-BLM) attached to a gold electrode,
an electrical circuit is created.
 Capture molecules such as antibodies can be bound to the
ion channel so that the binding of the target molecule controls
the ion flow through the channel. This results in a measurable
change in the electrical conduction which is proportional to the
concentration of the target.

17. The appropriate placement of biosensors depends on their field
of application, which may roughly be divided into,
Biotechnology
Agriculture
Food technology
biomedicine

18.  Highly specific
 Easy to use , Durable
 Require only small sample volume
 Rapid, Accurate, Stable and STERILIZABLE

19. :

20.  Detection of viral ,fungal ,bacterial diseases of plants.
 In food industry, detection of total microbes & food
quantification in soft drinks.
 To determine the freshness of other fish, beef and other
food items.
 Makes bacteria GLOW by OPTICAL biosensor

21. Pregnancy Test:
 Detects the HCG protein in urine.
 Interpretation & data analysis performed
by the user.
Infectious Disease
Biosensor:
 Data analysis and interpretation
performed by microprocessor