Oral Microbe Project

There is fascinating chemistry in the microbial population within the human mouth. In this project, students test their own saliva for the presence of specific species of bacteria. The students will collect their saliva and purify it to extract the microbial DNA that may be present. Then, students perform PCR to amplify genes unique to these different species. Students construct a lateral flow biosensor and use it to detect the presence or absence of these genes through a colorimetric readout.

Biosensors are thin test strips that use flow-through capillary action to separate and detect specific DNA sequences on a porous support, giving distinct color lines as a positive signal. Biosensors consists of four sections: the immersion pad, which is made of cellulose and is the part of the biosensor placed in the dipstick solution; the conjugation pad made of glass fiber, where the sample and the colored particles are added; the nitrocellulose membrane, where the DNA probe sequences are attached; and the absorption pad, also made of cellulose, which absorbs unbound particles. The students will then be able to determine if any of the species selected are present in their own saliva.


Lia Tucker and Saumini Shah began work on the project in the summer of 2009. Cary Lipovsky and Aaron Philips have continued working on the project, and we plan to pilot test the project in high school classrooms in the spring of 2010.

  • Two undergraduates working on the oral microbe project.