By Dominic Lanni

Part One

Introduction  What are biosensors?  A device that uses a living organism or biological molecule to detect things  Usually chemicals, heavy metals, pathogens

Famous Person  Pioneer of technology is Anthony P. F. Turner  Introduced screen- printing techniques  Developed blood- glucose sensors for diabetics

Types of Biosensors  Can be Electrochemical (Amperometry) Electrical (Conductivity) Optical (Fluorescence) Mass Sensitive (Piezoelectric frequency) Thermal (Heat of reaction/adsorption)

Part Two

Purpose  Dysentery-not fun (duh)  Caused by an amoeba or a bacterium called Shigella  No vaccine available (although there are treatments)  Proposal: a Mass-Sensitive Biosensor Will detect bacteria in water

Competing Technologies  Conventional bacterial cultures  Immunological methods  Molecular microbiological methods

The Design  Mass-sensitive Utilizes piezoelectric quartz crystal  DNA probe attached to crystal  Water sample put through DNA isolation process, and heated to denature strands PCR may also be performed

The Design  DNA is pipetted in, and heated to 50 degrees Celsius  Strands anneal to probe, increasing mass of crystal  Change in mass creates change in frequency  Change in frequency signals presence of Shigella

Expected Results  If the frequency emitted by the crystal changes, then DNA has bound to probe  If DNA binds to probe, then Shigella bacteria are present in water sample  Knowledge of contamination prevents spreading and contraction of dysentery

Advantages  No lack of supplies, as in bacterial cultures  Can be extremely fast  Crystals are cheap

Potential Problems  Could be difficult to assemble on a large scale  PCR would slow down process if necessary for success  Portable power source for whole system necessary, as finding an outlet may be difficult  Crystals can degrade in quality over time

Testing  Tests to determine how accurate device is  Tests to determine if PCR is necessary or not  Environmental tests to determine hardiness of device and crystals

Hope you learned something. I don’t care what. Anything is great.

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