World Library  
Flag as Inappropriate
Email this Article

Chemotaxis assay

Article Id: WHEBN0007265847
Reproduction Date:

Title: Chemotaxis assay  
Author: World Heritage Encyclopedia
Language: English
Subject: Chemotaxis, Chemotactic selection, Laboratory techniques, Boyden, Physiology
Collection: Laboratory Techniques, Molecular Biology, Perception, Physiology, Signal Transduction
Publisher: World Heritage Encyclopedia

Chemotaxis assay

Chemotaxis assays are experimental tools for evaluation of chemotactic ability of prokaryotic or eukaryotic cells. A wide variety of techniques are known and applied for such reason. Some of them qualitative and investigator can determine whether the cells prefer or not the tested chemical, others are quantitative and we can get information about the intensity of the responses in a more detailed way.


  • Quality control 1
  • Agar-plate techniques 2
  • Two-chamber techniques 3
    • Boyden chamber 3.1
    • Bridge chambers 3.2
    • Capillary techniques 3.3
  • Other techniques 4
  • References 5
  • External links 6

Quality control

In general, the most important requisite is to calibrate the incubation time of the assay both to the model cell and the ligand to be evaluated. Too short incubation time results no cells in the sample, while too long time perturbs the concentration gradients and measures more chemokinetic than chemotactic responses.

The most commonly used techniques are grouped into two main groups:

Agar-plate techniques

Chemotaxis assays with agar plates

This way of evaluation deals with agar-agar or gelatine containing semi-solid layers made prior to the experiment. Small wells are cut into the layer and filled with cells and the test substance. Cells can migrate towards the chemical gradient in the semi solid layer or under the layer as well. Some variations of the technique deal also with wells and parallel channels connected by a cut at the start of the experiment (PP-technique). Radial arrangement of PP-technique (3 or more channels) provides the possibility to compare chemotactic activity of different cell populations or study preference between ligands.[1]

Counting of cells: positive responder cells could be counted from the front of migrating cells, after staining or in native conditions in light microscope.

Two-chamber techniques

Chemotaxis chamber assays

Boyden chamber

Chambers isolated by filters are proper tools for accurate determination of chemotactic behavior. The pioneer type of these chambers was constructed by Boyden.[2] The motile cells are placed into the upper chamber, while fluid containing the test substance is filled into the lower one. The size of the motile cells to be investigated determines the pore size of the filter; it is essential to choose a diameter which allows active transmigration. For modelling in vivo conditions, several protocols prefer coverage of filter with molecules of extracellular matrix (collagen, elastin etc.) Efficiency of the measurements was increased by development of multiwell chambers (e.g. NeuroProbe), where 24, 96, 384 samples are evaluated in parallel. Advantage of this variant is that several parallels are assayed in identical conditions.

Bridge chambers

In another setting the chambers are connected side by side horizontally (Zigmond chamber)[3] or as concentric rings on a slide (Dunn chamber)[4] Concentration gradient develops on a narrow connecting bridge between the chambers and the number of migrating cells is also counted on the surface of the bridge by light microscope. In some cases the bridge between the two chambers is filled with agar and cells have to "glide" in this semisolid layer.

Capillary techniques

Some capillary techniques provide also a chamber like arrangement, however, there is no filter between the cells and the test substance.[5] Quantitative results are gained by the multiwell type of this probe using 4-8-12-channel pipettes. Accuracy of the pipette and increased number of the parallel running samples is the great advantage of this test.[6]

Counting of cells: positive responder cells are count from the lower chamber (long incubation time) or from the filter (short incubation time). For detection of cells general staining techniques (e.g. trypan blue) or special probes (e.g. mt-dehydrogenase detection with MTT assay) are used. Labelled (e.g. fluorochromes) cells are also used, in some assays cells get labelled during transmigration the filter.

Other techniques

Other chemotaxis assay techniques

Besides the above-mentioned two, most commonly used family of techniques a wide range of protocols were developed to measure chemotactic activity. Some of them are only qualitative, like aggregation tests, where small pieces of agar or filters are placed onto a slide and accumulation of cells around is measured.

In another semiquantitative technique cells are overlaid the test substance and changes in opalescence of the originally cell-free compartment is recorded during the incubation time.[7]

The third very frequently used, however, qualitative technique is the T-maze and its adaptations for microplates. In the original version a container drilled in a peg is filled with cells. Then the peg is twisted and the cells get contact with two other containers filled with different substances. The incubation is stopped with resetting the peg, the cell number is counted from the containers.[8]


  1. ^ Kőhidai L. (1995). "Method for determination of chemoattraction in Tetrahymena pyriformis.". Curr Microbiol 30 (4): 251–3.  
  2. ^ Boyden, S.V. (1962). "The chemotactic effect of mixtures of antibody and antigen on polymorphonuclear leucocytes.". J Exp Med 115 (3): 453–66.  
  3. ^ Zigmond S.H. (1977). "Ability of polymorphonuclear leukocytes to orient in gradients of chemotactic factors". J. of Cell Biology 75 (2): 606–616.  
  4. ^ Zicha D., Dunn G.A., Brown A.F. (1991). "A new direct-viewing chemotaxis chamber.". J Cell Sci 99: 769–75.  
  5. ^ Leick V.and Helle J. (1983). "A quantitative assay for ciliate chemotaxis.". Anal Biochem 135 (2): 466–9.  
  6. ^ Kőhidai, L., Lemberkovits, É. and Csaba, G. (1995). "Molecule dependent chemotactic responses of Tetrahymena pyriformis elicited by volatile oils.". Acta Protozool 34: 181–5. 
  7. ^ Koppelhus U., Hellung-Larsen P. and Leick V. (1994). "An improved quantitative assay for chemokinesis in Tetrahymena.". Biol Bull (Marine Biological Laboratory) 187 (1): 8–15.  
  8. ^ Van Houten J., Martel E. and Kasch T. (1982). "Kinetic analysis of chemokinesis of Paramecium.". J Protozool 29 (2): 226–30.  

External links

  • Chemotaxis
  • Cell Migration Gateway
  • Cytometric chemotaxis and cell migration assay
  • Free tool based on ImageJ to analyse chemotactical processes
  • Chemotaxis Image Analysis Tool
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.