Biolayer interferometry (BLI) is a label-free optical method that measures binding events at the tip of a fiber-optic biosensor in real time. In research peptide analysis, BLI is used in the laboratory to study binding kinetics and affinity between a peptide and its binding partner under controlled conditions.

How the method works: One binding partner is immobilized on the biosensor tip, and the tip is dipped into wells containing the other partner at a series of concentrations. Binding shifts the interference pattern of reflected light, producing association and dissociation curves from which researchers estimate kinetic rate constants and an equilibrium dissociation constant in vitro. Controls typically include reference sensors, buffer-only wells, and checks for nonspecific binding.

Applications and limits: BLI uses small sample volumes, tolerates crude samples better than some surface methods, and needs no labeling, which makes it useful for peptide interaction screening in research settings. Results depend on immobilization strategy, sensor chemistry, and sample quality, so laboratories confirm key findings with an orthogonal method such as surface plasmon resonance, and verify peptide identity and purity by HPLC and mass spectrometry first.

Disclaimer: This article is for laboratory research purposes only. Not for human consumption. Not for medical, therapeutic, diagnostic, or veterinary use. No dosing, reconstitution-for-use, or efficacy information is provided or implied.

Citations: Standard BLI method literature on interferometry and binding-kinetics analysis; HPLC/MS peptide characterization methods.