> For the complete documentation index, see [llms.txt](https://help.sbtinstruments.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sbtinstruments.com/advanced/measurements-explained/what-is-bactobox.md). # How BactoBox® works BactoBox® uses impedance flow cytometry (IFC). That sounds very technical, but let's look at each words one by one in the next sections. {% embed url="" %} BactoBox® explainer. For best experience turn on sound :headphones:. {% endembed %} ## Impedance Impedance is the cell’s resistance to electrical current. All cells have lipid membranes, and lipid membranes do not conduct electricity well. Because of this, the membrane acts as a barrier that changes how electrical current flows between the electrodes when a cell passes through the measurement area. * At low electrical measurement frequencies current mostly goes around the bacterium because the membrane acts like an insulator * At high electrical measurement frequencies current can partly pass through the cell membrane and probe the inside of the bacterium. The cytoplasm of cells is usually rich in ions and is good at conducting electricity.

BactoBox® measurement principle. The membrane and cytoplasm of cells creates a distinct electrical signature.

## Flow Flow means movement of liquid. This is what we refer to when liquid is passing through the flow cell. BactoBox® can determine the flow rate by measuring how fast an object travels between electrode sets. ## Cytometry Cyto means cell. Metry means "to measure". So cytometry is any method used to measure properties of cells such as number of cells, size, shape, and electrical properties. BactoBox® counts cells by counting objects with distinct membrane-like features when these are moving past the electrodes. ## Impedance flow cytometry Now that we know what each word means let's try to put it in into practical relevance. BactoBox® uses IFC to determine the concentration of bacteria. This is similar to fluorescence flow cytometry (FFC) in that objects traverse the detector element in a single file. Unlike FFC, which uses lasers, BactoBox® uses an electric field as its detector element. The lipid membrane of bacteria and conductive cytoplasm provides a distinct signature that enables specific detection of bacteria without the need for staining. In other words, BactoBox® uses IFC to enable easy, fast, precise, and specific enumeration of cells. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://help.sbtinstruments.com/advanced/measurements-explained/what-is-bactobox.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.