CHEMISTRY & PHYSICS OF THE BIOSENSOR

More of the Capture Membrane!

Polyaniline and CNT’s are used in the Capture Membrane

POLYANILINE: an important nanotech plastic

• A conducting, organic plastic often used with CNT’s

• Can tell whether an acid or base is in the air

• Sensitivity to an acid or base increases with surface area

• Surface area is determined in the creation of the polyaniline by creating more bumps and valleys that are nano size.

• The Conductivity changes due to exposure to acid (vinegar) or a base (ammonia).

POLYANILINE: a material of promise!

• The amount of required conductivity is designed into the pani (polyaniline)

• It can be melted into a liquid easily• Or it can be put into solution (like sugar & water)• It’s easy to make required shapes with pani• No environmental problems with disposal

PANI – applications since 2000• Electronics

– Super-capacitors– Super-magnets– Integrated circuits– Luminescent diodes– Sensors

• Chemical Power sources

• Conductive fabrics

• Anti static coatings

PANI/CNT SENSORS

• POLYANILINE attached to CNT can become excellent sensors of bacteria & viruses!

• Why would we want to develop this????

Earlier you found out what Temperatures and PH’s

PANI was more conductive at.

What were your results??

Do you remember??

The Biosensor & it’s basic parts

PHYSICS STUDENTS• What do you think the circuit looks like?

• Is it a parallel or series circuit?

• What could be used that is small enough for a voltage source?

• When the antigen is found – how will that close the switch to send the electronic signal?

• How will we want to know that the signal has been sent? What’s practical here?

The Capture Membrane & the Circuit Diagram

Assignment A:

• You will be building a large scale biosensor circuit.

• You will want to capture something large (such as a magnet or a toy car) as it travels past your circuit. This will be your switch.

• Use a voltage source of a battery of appropriate size.

• When your switch is closed (on) have it light up a light bulb or turn on a buzzer.

• Design into your circuit appropriate places for a Ammeter.

Parameters of the Project(teams of 2)

• Draw a circuit diagram and have your teacher approve it.

• Make a list of supplies needed & have your teacher approve it.

• Make a list of tests you should run once it’s working & have your teacher approve it.

• Build it! Ask your teacher for help if you are having trouble getting it to work.

• Run your tests! Analyze your data & write a conclusion!