Quantitative analysis of single bacterial chemotaxis using a linear concentration gradient microchannel.
A microfluidic device to quantify bacterial chemotaxis has been proposed, which generates a linear concentration gradient of chemoattractant in the main channel only by convective and molecular diffusion, and which enables the bacteria to enter the main channel in a single file by hydrodynamic focusing technique. The trajectory of each bacterium in response to the concentration gradient of chemoattractant is photographed by a CCD camera and its velocity is acquired by a simple PTV (Particle Tracking Velocimetry) algorithm. An advantage of this assay is to measure the velocity of a single bacterium and to quantify the degree of chemotaxis by analyzing the frequency of velocities concurrently. Thus, the parameter characterizing the motility of wild-type Escherichia coli strain RP437 in response to various concentration gradients of L-aspartate is obtained in such a manner that the degree of bacterial chemotaxis is quantified on the basis of a newly proposed Migration Index.
Jeon
Hojeong
H
School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744, Korea.
Lee
Yongku
Y
Jin
Songwan
S
Koo
Sangmo
S
Lee
Chang-Soo
CS
Yoo
Jung Yul
JY
D002633:Chemotaxis; D004926:Escherichia coli / Q000166:cytology*; D057446:Hydrodynamics; D007267:Injections; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*