Creative Biolabs proudly provides you the Octet system from ForteBio for measuring antibody affinity. The Octet platform based on bio-layer interferometry (BLI) technology is a whole set of system including instruments, biosensors, reagents and assay kits to support the evaluation of biomolecular interactions in 96- or 384-well microplates. Octet system uses Dip-and-Read assay mode avoiding the need of microfluidics, and enables the real-time, label-free analysis of affinity as well as kinetics. Compared to the standard Biacore system, Octet has a higher throughput that provides greater potential in drug development applications. Additionally, Octet utilizes nm shift rather than response unit to define surface changes, which makes it much easier- and faster- in manipulation and cost-effective for antibody affinity measurement.
The principle of BLI technology is based on the optical interference pattern of white light reflected from two surfaces - a layer of immobilized protein and an internal reference layer. The binding between a ligand immobilized on the biosensor tip surface and an analyte in solution produces an increase in optical thickness at the biosensor tip, which results in a shift in the interference pattern measured in nanometers. The wavelength shift (Δλ) is a direct measure of the change in optical thickness of the biological layer, when this shift is measured over a period of time and its magnitude plotted as a function of time, a classic association/dissociation curve is obtained. This interaction is measured in real-time, providing the ability to monitor binding specificity, association rate and dissociation rate, and concentration with outstanding precision and accuracy.
Figure 1. The principle of BLI technology.
There are three biosensor-based assay orientations that can be used to explore antibody interaction (Figure 2): tandem blocking, premix blocking and classical sandwich. Compared to Biacore, Octet’s dip-and-read assay allows longer analyte-binding steps and favors the rebinding of analyte to the ligand-coated sensors. Meanwhile, faster association time consumes less sample, which saves your precious proteins.
Figure 2. Outline of three biosensor-based assay orientations: (A) in tandem blocking; (B) premix blocking; and (C) classical sandwich.Key Features of Octet system:
It is worth to mention that, if you need to compare a series of antibodies that target different regions with similar affinity constants, we are capable of perform epitope binning to evaluate each antibody separately. The antigen is captured onto the biosensor and the first antibodies are introduced to saturate the antigen, then the competing antibody is applied and measured with the kinetic curve getting determined to provide further characterization of the specificity. All of these could have significant effects for candidates’ efficiency and pharmacokinetics evaluation.