Guide

Static vs Kinetic SPR

When to use each mode, what data you get, and how they compare: static on the P4SPR 2.0, kinetic on the P4PRO with AffiPump.

FormatOne-page cheat sheet

CoversStatic (endpoint) and kinetic (flow) SPR

The two modes

Static SPR

Endpoint Screening

Scouting and screening before kinetic SPR — yes/no binding, concentration determination, quick verification.

Static SPR: diffusion-based analyte delivery across two independent channels on the gold sensor surface

Like label-free ELISA: ligand–analyte interaction depends on diffusion, concentration, and binding strength
Binding measured as Apparent K_D from concentration titration at ½ RU_max
Concentration determination of active analyte in complex media (e.g. crude lysate)
Quick verification of protein expression
Contact time seconds to hours — slow interactions can be measured
Low viscosity buffers and biomolecules 10–500 kDa recommended²
Up to 4 independent experiments (4 channels) on the P4SPR 2.0¹

Kinetic SPR

Quantitative Binding

Sensitive, real-time binding characterization — both the strength and rate of binding are measured.

Kinetic SPR: continuous flow delivers analyte across immobilized ligand on the gold sensor surface

Constant flow of analyte — both strength and rate of binding measured
Quantitative K_D = k_off / k_on from kinetic fitting
Can transfer static SPR conditions directly to kinetic mode
Controlled flow accommodates a broader range: 100+ Da to 500+ kDa
Suitable for low analyte concentrations — better real-time sensitivity
Steeper upward curve = faster association; steeper downward = faster dissociation
Up to 2 independent experiments (4 channels, 2 with reference) on the P4PRO with AffiPump¹

What the data looks like

Static SPR: the curve rises and levels off, read at the endpoint. Kinetic SPR: the curve rises, then falls back as the analyte leaves under flow — Static SPR reads one value at the end of the contact time; kinetic SPR follows both the binding and the release. Illustration by Affinité Instruments.

Static SPR Output

Association without dissociation
End-point response units are analyzed
Apparent K_D estimated at ½ RU_max from concentration titration

Kinetic SPR Output

Both association and dissociation measured in real time
Quantitative K_D calculated from k_off / k_on
Steeper upward curve = faster association; steeper downward = faster dissociation

Side by side

	Static SPR	Kinetic SPR
Use case	Screening, end-points	Real-time binding characterization
Binding parameters	Apparent K_D	k_on, k_off, K_D
Concentration determination	Yes	Yes
Analyte size range	10 kDa – 500 kDa²	100 Da – 500+ kDa
Analyte types	Peptides, antibodies, protein complexes	Small molecules, peptides, antibodies, nanoparticles, vesicles
Experiments per run	Up to 4 independent¹	Up to 2 independent (4 channels)
Ligand required	> 10 µg	> 10 µg
Sample injection	Manual	Semi-automated (P4PRO with AffiPump)
Average assay time	5 – 15 min	5 – 20 min

¹ Four different conditions (media, surface chemistries, ligands, etc.) in one setup using the P4SPR.
² In some cases, small molecules and large nanoparticles can also be used — contact us for details.

Methods often used alongside SPR

Western blot · ELISA · Immunoprecipitation · Isothermal calorimetry (ITC) · Biolayer interferometry (BLI) · Fluorimetry · Atomic force microscopy (AFM)