Generally, switchSENSE® can tolerate measurements in a variety of complex matrices, including cell lysates and high serum concentrations up to 80 %. Nevertheless, measurements in complex media usually require a certain degree of assay development. In most cases, this is owed to the occurrence of unspecific adsorption to surfaces of the sensor system. For successful experiments, please consider the following aspects:
- Always filter samples or remove solid components by centrifugation prior to injection.
- The addition of non-specific competitor substances (fragmented salmon sperm DNA, polydIdC) is usually required to reduce background affinity.
- When using salmon sperm DNA or similar reagents, make sure to use a well buffered solution to avoid acidification.
- Measurements in static mode are usually more robust when complex media are tested.
- The activity of nucleases that are potentially present in the test solution, is often reduced by EDTA.
- Always perform a reference injection on DNA nanolevers without ligand.
- As complex media usually differ significantly in composition, the ideal dilution of the original sample should be optimized.