switchSENSE® chips are very versatile, typically long-lasting and can be used for a multitude of different experiments, due to the possibility of chip regeneration. During the course of the experiments, the sensor electrodes are subjected to a certain decrease of fluorescence intensity which limits their lifespan. Furthermore, potentially harmful experimental conditions, such as high temperatures, organic solvents or extreme pH values, can negatively affect the chip viability. To ensure ideal conditions for your experiment, it is thus important to assess the quality of the sensor electrodes prior to an experiment. This is particularly advisable when a flow channel has been in use for several experimental runs. Please note that for a chip status measurement the DNA nanolevers must be in double-stranded state without attached ligand molecules. If this is not the case or if you are not sure about the state of the DNA nanolevers, please select “with regeneration” in the chip status dialog.
The chip status test is a tool that quickly provides information on the quality of all electrodes of a selected flow channel under standard conditions. After a few minutes, the tested electrodes are ranked in three categories:
- Red: Bad electrode viability. Do not use this electrode anymore!
- Yellow: Moderate electrode viability. This electrode can still be used but should be avoided for very long experiments or experiments performed under harsh conditions.
- Green: Good electrode viability.
As the lifetime of an electrode is affected by different factors, these rankings can only provide guidance for planning of your experiment. Thus, in addition to the chip status test you should always consider the following aspects:
- Under mild conditions, electrodes ranked as moderate can still be used for many experiments, including several regeneration steps.
- Electrodes used for experiments performed at a very low surface density, typically are ranked as moderate or even bad. This is expected but certainly limits the number of experiments that can be performed on such an electrode. We advise to use a fresh electrode for every low-density experiment.
- Although all electrodes inside one flow channel are exposed to identical chemical and thermal conditions, electrodes that are not actively used during experiments (i.e. not continuously illuminated) usually show a significantly less pronounced loss in fluorescence intensity.
- If you’d like to perform your experiment under harsh conditions, we advise to test these conditions under the experimental preferences that you intend to use (binding times, temperature, number of regenerations) using only one electrode of the flow channel.