Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic Device
Chemotaxis refers to the ability of organisms to detect chemical gradients and bias their motion accordingly. Quantifying this bias is critical for many applications and requires a device that can generate and maintain a constant concentration field over a long period allowing for the observation of...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Bio-protocol LLC
2025-02-01
|
| Series: | Bio-Protocol |
| Online Access: | https://bio-protocol.org/en/bpdetail?id=5184&type=0 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1850072088497356800 |
|---|---|
| author | Adam Gargasson Carine Douarche Peter Mergaert Harold Auradou |
| author_facet | Adam Gargasson Carine Douarche Peter Mergaert Harold Auradou |
| author_sort | Adam Gargasson |
| collection | DOAJ |
| description | Chemotaxis refers to the ability of organisms to detect chemical gradients and bias their motion accordingly. Quantifying this bias is critical for many applications and requires a device that can generate and maintain a constant concentration field over a long period allowing for the observation of bacterial responses. In 2010, a method was introduced that combines microfluidics and hydrogel to facilitate the diffusion of chemical species and to set a linear gradient in a bacterial suspension in the absence of liquid flow. The device consists of three closely parallel channels, with the two outermost channels containing chemical species at varying concentrations, forming a uniform, stationary, and controlled gradient between them. Bacteria positioned in the central channel respond to this gradient by accumulating toward the high chemoattractant concentrations. Video-imaging of bacteria in fluorescent microscopy followed by trajectory analysis provide access to the key diffusive and chemotactic parameters of motility for the studied bacterial species. This technique offers a significant advantage over other microfluidic techniques as it enables observations in a stationary gradient. Here, we outline a modified and improved protocol that allows for the renewal of the bacterial population, modification of the chemical environment, and the performance of new measurements using the same chip. To demonstrate its efficacy, the protocol was used to measure the response of a strain of Escherichia coli to gradients of α-methyl-aspartate across the entire response range of the bacteria and for different gradients. |
| format | Article |
| id | doaj-art-66dc9399dac34d04b9726585172fbc49 |
| institution | DOAJ |
| issn | 2331-8325 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Bio-protocol LLC |
| record_format | Article |
| series | Bio-Protocol |
| spelling | doaj-art-66dc9399dac34d04b9726585172fbc492025-08-20T02:47:09ZengBio-protocol LLCBio-Protocol2331-83252025-02-0115410.21769/BioProtoc.5184Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic DeviceAdam Gargasson0Carine Douarche1Peter Mergaert2Harold Auradou3Université Paris-Saclay, CNRS, FAST, 91405, Orsay, FranceUniversité Paris-Saclay, CNRS, FAST, 91405, Orsay, FranceUniversité Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, 91198, Gif-sur-Yvette CEDEX, FranceUniversité Paris-Saclay, CNRS, FAST, 91405, Orsay, FranceChemotaxis refers to the ability of organisms to detect chemical gradients and bias their motion accordingly. Quantifying this bias is critical for many applications and requires a device that can generate and maintain a constant concentration field over a long period allowing for the observation of bacterial responses. In 2010, a method was introduced that combines microfluidics and hydrogel to facilitate the diffusion of chemical species and to set a linear gradient in a bacterial suspension in the absence of liquid flow. The device consists of three closely parallel channels, with the two outermost channels containing chemical species at varying concentrations, forming a uniform, stationary, and controlled gradient between them. Bacteria positioned in the central channel respond to this gradient by accumulating toward the high chemoattractant concentrations. Video-imaging of bacteria in fluorescent microscopy followed by trajectory analysis provide access to the key diffusive and chemotactic parameters of motility for the studied bacterial species. This technique offers a significant advantage over other microfluidic techniques as it enables observations in a stationary gradient. Here, we outline a modified and improved protocol that allows for the renewal of the bacterial population, modification of the chemical environment, and the performance of new measurements using the same chip. To demonstrate its efficacy, the protocol was used to measure the response of a strain of Escherichia coli to gradients of α-methyl-aspartate across the entire response range of the bacteria and for different gradients.https://bio-protocol.org/en/bpdetail?id=5184&type=0 |
| spellingShingle | Adam Gargasson Carine Douarche Peter Mergaert Harold Auradou Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic Device Bio-Protocol |
| title | Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic Device |
| title_full | Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic Device |
| title_fullStr | Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic Device |
| title_full_unstemmed | Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic Device |
| title_short | Quantifying Bacterial Chemotaxis in Controlled and Stationary Chemical Gradients with a Microfluidic Device |
| title_sort | quantifying bacterial chemotaxis in controlled and stationary chemical gradients with a microfluidic device |
| url | https://bio-protocol.org/en/bpdetail?id=5184&type=0 |
| work_keys_str_mv | AT adamgargasson quantifyingbacterialchemotaxisincontrolledandstationarychemicalgradientswithamicrofluidicdevice AT carinedouarche quantifyingbacterialchemotaxisincontrolledandstationarychemicalgradientswithamicrofluidicdevice AT petermergaert quantifyingbacterialchemotaxisincontrolledandstationarychemicalgradientswithamicrofluidicdevice AT haroldauradou quantifyingbacterialchemotaxisincontrolledandstationarychemicalgradientswithamicrofluidicdevice |