A new approach

SBT has developed and applied a new technology for bacteria measurements

Our approach to developing next-generation innovative measurement solutions at SBT is built upon close collaboration between several different technical fields. This is what enables us to challenge status quo and improve the state-of-the-art. In 2013, the SBT founders saw an opportunity to solve the pains several industries had with the 100-year-old plate count method.

This resulted in BactoBox, a technology for measuring bacteria using electrical impedance as a detection principle. This technology solves the pains of plate counts and other technologies by being both fast, accurate, easy-to-use and affordable.

Our approach to developing next-generation innovative measurement solutions at SBT is built upon close collaboration between several different technical fields. This is what enables us to challenge status quo and improve the state-of-the-art. In 2013, the SBT founders saw an opportunity to solve the pains several industries had with the 100-year-old plate count method.

This resulted in BactoBox, a technology for measuring bacteria using electrical impedance as a detection principle. This technology solves the pains of plate counts and other technologies by being both fast, accurate, easy-to-use and affordable.

How impedance flow cytometry works

Flow cytometry involves measuring the characteristics of cells in a flow. Impedance flow cytometry is measuring cell characteristics in a flow using electrical impedance as a detection method. In SBTs technology, this is achieved by running the user’s sample through a microfluidic flow cell with integrated electrodes that can detect and assess any objects between 0.5 and 5 µm.

When an object flows between the electrodes in the flow cell, the magnitude of current running between the electrodes will change and an event is detected. The change in current is distinct for living cells since they conduct electricity differently than particles due to their intact cell membranes and cytoplasm. This enables our technology to accurately detect all bacterial cells in the sample while omitting particles and dead bacteria with non-intact membranes from the count. The result is an accurate count of Intact Cells per millilitre in just 2 minutes.

Intact cells is a direct measure of all the bacteria in the sample. This is a different approach from e.g. plate counts where only culturable bacteria are measured as Colony Forming Units (CFU). Since some bacteria species grow better at different temperatures, at different ambient conditions, and on different nutritional media, and many do not grow on plates at all, the count in the same sample differs significantly between chosen growth conditions. As a result, most samples will usually show higher Intact cells than CFU, especially when a high fraction of non-culturable bacteria are present e.g. in natural waters. In contrast, in cases where all bacteria are culturable on plates, such as in bacteria fermentations or when working with pure cultures, the correlation between plate counting CFU and SBT's Intact cells is linear and approximately 1:1.