Table 1.

Comparison of surface plasmon resonance (SPR) and biolayer interferometry (BLI) to other common binding assays.

Assay	Method Overview	Advantages	Limitations
SPR [19]	Binding measured with one immobilized partner and one partner in flow chamber by reflection of light.	Label-free, real-time kinetic	Regeneration optimization [16,24] Non-specific binding One immobilized partner
BLI	Binding measured with one partner immobilized and one diluted partner in plate well by reflection of light.	Label-free, real-time kinetic	Sample evaporation over time [25] Agitation required to prevent re-binding [25] One immobilized partner Regeneration optimization Non-specific binding
Enzyme-linked immunosorbent assay (ELISA)	Binding measured as surface adsorption between both binding partners by chemical colorimetric signal [19].	Label-free	Not real-time Several buffers Plate-based immobilization Signal based on secondary antibody [19] Non-specific binding
Isothermal Titration Calorimetry (ITC) [20]	Binding measured in solution by enthalpy changes from binding event.	Label-free, real-time kinetic	High sensitivity to matrix changes and non-specific enthalpic events
Flow Cytometry [26,27]	Binding measured between two suspended partners using fluorescence and light scattering.	Supports cell-based assays	Not real-time Fluorescent labeling required