switchSENSE® is a biophysical research technology to investigate molecular interactions. The core of this technology are DNA nanolevers attached to gold microelectrodes. These DNA nanolevers can easily be customized with any ligand of choice. The orientation of the nanolevers can be controlled by applying voltage to the microelectrodes. We differentiate two measurement modes in switchSENSE® experiments, the dynamic mode and the static mode. In dynamic mode, an alternating voltage is applied, causing the negatively charged DNA nanolevers to oscillate at high frequencies. In static mode, a negative voltage is applied to hold the nanolevers in a static, upright orientation. The nanolevers are additionally equipped with a fluorescent dye. The readout signal of a switchSENSE® experiment is a change in fluorescence intensity. This can be caused by multiple events. For example, the local environment of the dye can change due to e.g. binding of an analyte to the ligand. Furthermore, the gold electrode surface quenches the dye, thus changes in the distance between the dye and the sensor surface will affect the fluorescence intensity. Some assays also include a second fluorescent dye and changes in intensity are caused by Förster resonance energy transfer (FRET) between the two dyes (see Which options do I have for dual-color assays? for details). Based on these measurement modes you can characterize your molecular interactions in great detail, ranging from kinetic rates to conformational changes of binding partners. Find out more about the technical details of switchSENSE®  here.

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