Field Effect Biosensing: An Electrical Sensing Mechanism for Kinetic Characterization
In a world full of daisies, dare to be a rose
As a scientist, you have preferred, go-to methods for testing molecular interactions, such as surface plasmon resonance (SPR), Bio-Layer Interferometry (BLI), ELISA, or fluorescence labeling. Each assay has its pros – label-free, accurate, simple, or you (or your lab tech) can perform it in-house. Each method also has its cons – requiring too many complicated steps, requiring a tag that interferes with the interaction, or needing to be outsourced to a CRO (which costs much more than your trusty lab tech). For every experiment, you’re left trying to balance time and cost with accuracy and the integrity of your interaction.
The problem with optics and small molecules
So, what is the best method to use if you’re measuring a small molecule therapeutic drug interacting with a targeted protein? If you require kinetic information without the complexity of labels, ELISA and fluorescence labeling are out. SPR and BLI are label-free kinetic binding systems that use optics and light to measure the mass of the small molecule as it interacts with immobilized protein. Since they are mass-based sensing techniques, the smaller the molecule, the more expensive the optics required to sense at a low limit of detection, making high-quality versions of these tools challenging for the general science community to access. Is there another way?
Achieve more with a new label-free method
Introducing the label-free, kinetic characterization technique Field Effect Biosensing (FEB) that can be used quickly in-house. FEB is an electrical mechanism that is highly sensitive to change in surface charge distribution when an interaction occurs; great news for small molecules which have high charge-to-mass ratios and are easily sensed by an FEB device. FEB systems also excel at detecting changes in localized charge at the molecular interface during interactions with larger molecules such as proteins and antigens, so you can quickly characterize proteins and small molecules in your own lab. Since FEB senses charge with a graphene biosensor instead of mass with optics, it can easily measure interactions in dirty, cloudy samples (think serum or blood) and bodes well with buffer additives such as dimethyl sulfoxide (DMSO) or bovine serum albumin (BSA) for target analyte that require more complex buffers.
The beauty of FEB is that is an entirely orthogonal technology to SPR and BLI and opens a new realm of possible experiments.