Lab on a Chip for Gram staining

The iPrint and iRAP institutes are working with Swissmeca to design and implement a new method for Gram staining that will drastically reduce reagent consumption and costs.

How can this be done? By using a lab-on-a-chip where the fluids are stored beforehand. Unlike other polypropylene microfluidic chips, the solution proposed in this project is extremely simple and compact.

In order to identify bacterial infections and provide the appropriate antibiotic treatment, it is essential to determine whether the bacteria responsible for the infection are of the Gram-positive or Gram-negative family.

To perform a Gram stain, 4 staining reagents based on water, alcohol and acetone are applied to bacteria fixed on a glass slide. Gram staining can be performed manually with pipettes or with automatic devices. The liquids used are chemically aggressive and potentially carcinogenic (acetone). Existing methods have several disadvantages: the reliability of the results depends on the skill of the operator; high consumption of dyes and reagents; the operator is potentially exposed to toxic fumes and solvents.

This new analysis technique has many advantages over manual and automatic staining methods:

• Reduced dye consumption
• The staining protocol is highly reliable and repeatable, and does not depend on the dexterity of the operator.
• The dyes remain entirely on the chip, the operator is not exposed to the dyes and vapours,
• Cost savings