Principle

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The BioFilm Ring Test® technology is the basis of the Antibiofilmogram®, Enzyme Ring Test®, and Affinity Ring Test® applications and is designed to measure the movement of superparamagnetic microbeads in a microplate submitted to a magnetic field by way of a magnet placed beneath the centre of the well.

Total or partial attenuation of the movement of these microbeads reflects a biological phenomenon (formation of a bacterial biofilm trapping the microbeads, modification of viscosity of the medium, macromolecular or cellular complexes making up obstacles …).

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Example of application

From an isolation, a defined bacterial culture is associated to suspension of magnetisable particles and placed in the wells of a microplate (200µL per well). The microplate is incubated at a suitable temperature usually for 4-6 h in order for the bacteria to adhere to the substrate and initiate biofilm formation. For the result reading phase, the microplate is removed  from incubator and firstly placed on a block containing 96 mini-magnets (centred under each well) for one minute then placed in a reader for bottom-reading of the well and immediately analysed by the BioFilm Control Elements® software which generates a Biofilm Index (score of 0 to 20, biofilm present to biofilm absent).

Results

If there is no biofilm the magnetisable particles are free to move and will group in the centre of the well above the mini-magnet to form a central spot (left-hand image). Alternatively, when a biofilm is formed, the particles are embeded, immobilised and no spot is visible (right-hand image). Depending on the degree of formation of the biofilm, an intermediate spot is generated (image of the centre). One example of application of this test is the search for efficient antibiotics to inhibit biofilm formation. (Original images read by the BioFilm Control reader)
Central spot

Central spot

No biofilm
Diffuse spot

Diffuse spot

Biofilm in formation
No spot

No spot

Biofilm formed

Applications

Microbial biofilm expertise

Microbial biofilm expertise

  • Bacteria, yeasts, microalgae
  • Sugar, matrix protein levels
  • Extraction of biofilm-specific compounds
  • Adherent biomass measurement
Antibiofilmogram ®

Antibiofilmogram ®

  • Efficacy testing of antibiotics on biofilm formation
  • Optimisation of antibiotic associations
Hygien product tests

Hygien product tests

  • Hygienogram
  • Aid in formulation
Immunology, haematology

Immunology, haematology

  • Detection of antigen-antibody complexes (Plasmodium, circulating antibodies, etc…)
  • Detection of surface antigens (red blood cell typing, etc)
Enzymology

Enzymology

  • Detection of bacterial depolymerising enzymes on vegetable polymers, etc (Enzyme Ring Test®)