2. Suppose that this immunosensor has been developed to detect two recently discovered antigen
targets, H1NoNo and H7R2D2. The affinity constants for these interactions are: kH1NOND 10-
3. H7R2D2 10+3 Explain in detail ifthis sensor will produce a valid output. Justify your answer
with a good explanation. (2 pts.)
Solution
Principles of immunosensors-
(a)(i) A tube is coated with (immobilised) antigen.
An excess of specific antibody-enzyme conjugate is placed in the tube and allowed to bind.
(a)(ii) After a suitable period any unbound material is washed off. (a)(iii) The analyte antigen
solution is passed into the tube, binding and releasing some of the antibody-enzyme conjugate
dependent upon the antigen\'s concentration as shown below diagrame.
The amount of antibody-enzyme conjugate released is determined by the response from the
biosensor. (b)(i) A transducer is coated with (immobilised) antibody, specific for the antigen of
interest. The transducer is immersed in a solution containing a mixture of a known amount of
antigen-enzyme conjugate plus unknown concentration of sample antigen. (b)(ii) After a suitable
period the antigen and antigen-enzyme conjugate will be distributed between the bound and free
states dependent upon their relative concentrations. (b)(iii) Unbound material is washed off and
discarded. The amount of antigen-enzyme conjugate bound is determined directly from the
transduced signal..
2. Suppose that this immunosensor has been developed to detect two re.pdf
1. 2. Suppose that this immunosensor has been developed to detect two recently discovered antigen
targets, H1NoNo and H7R2D2. The affinity constants for these interactions are: kH1NOND 10-
3. H7R2D2 10+3 Explain in detail ifthis sensor will produce a valid output. Justify your answer
with a good explanation. (2 pts.)
Solution
Principles of immunosensors-
(a)(i) A tube is coated with (immobilised) antigen.
An excess of specific antibody-enzyme conjugate is placed in the tube and allowed to bind.
(a)(ii) After a suitable period any unbound material is washed off. (a)(iii) The analyte antigen
solution is passed into the tube, binding and releasing some of the antibody-enzyme conjugate
dependent upon the antigen's concentration as shown below diagrame.
The amount of antibody-enzyme conjugate released is determined by the response from the
biosensor. (b)(i) A transducer is coated with (immobilised) antibody, specific for the antigen of
interest. The transducer is immersed in a solution containing a mixture of a known amount of
antigen-enzyme conjugate plus unknown concentration of sample antigen. (b)(ii) After a suitable
period the antigen and antigen-enzyme conjugate will be distributed between the bound and free
states dependent upon their relative concentrations. (b)(iii) Unbound material is washed off and
discarded. The amount of antigen-enzyme conjugate bound is determined directly from the
transduced signal.
