Skip to main content

Measure small molecule binding affinity and kinetics, label-free

Fragments, inhibitors, peptides. The inQuiQ resolves weak and short-lived binding in real time, on your own bench.
Sensitive detection at 0.1 RU RMS baseline noise
Affinity range from 10 pM to 10 mM
Contact time tuned by flow, 5 to 300 µL/min

Label-free binding data across compound classes

Every compound class brings its own binding question. inQuiQ answers them from one platform.

Fragments

Detect binding of fragments under 300 Da.

Confirm that a fragment binds at all.

weak binders

Enzyme inhibitors

Separate potency from residence time.

Two inhibitors with the same IC50 can have very different off-rates.

koff, residence time

Agonists and antagonists

Measure dose-response directly on the target.

Binding and inhibition measured on the same surface, in the same run.

IC50, EC50

Allosteric modulators

Find out where on the target a compound acts.

Competitive assays reveal where a compound binds.

orthosteric vs allosteric

Peptides

Measure peptide-protein kinetics across chemistries.

Test with assay-relevant solvents, salts, and additives.

various buffers possible

Don't see your compound class?

Discuss your assay with one of our application specialists.

Talk to a specialist

Benefits of the inQuiQ in small molecule research

01 / 04

One injection, four channels, sixteen sensors.

Four independently addressable flow channels, each carrying four sensors, with the sample flowing through the channels in series.

30 µL minimumsequential flow paths
In-flow immobilisation
Spotter immobilisation

A fragment-sized response still measurable

Low baseline noise resolves small mass changes, while flow rate controls target contact time. Affinity spans 10 pM to 10 mM, with steady-state fitting for fast dissociation.

0.1 RU RMSkon, koff, KD
weak binder still resolves

Measure in native, label-free conditions

The target meets the ligand without labels that could alter small-molecule binding.

  • No tag on a compound where extra mass would alter binding
  • Binding measured exactly as it happens in solution
the same binding event

See where the compound binds, not just how well

Inject the compound against a known site binder. Competition reveals whether both compounds share the same binding site.

competes
orthosteric
binds alongside
allosteric
competitive assaysIC50, EC50
blocked, or bound alongside

How small molecule binding run works

Every measurement follows the same steps, no matter the compound. The target is captured on the sensor, the compound flows past, and the instrument records the binding response in real time. An endpoint assay gives you one number. The inQuiQ gives you the full curve.

Immobilisation

The target protein is attached to the sensor surface first.

Amine coupling or capture through a tag holds it in place. This target-on-the-surface setup suits fragment-based drug discovery and peptide screening, with the compound injected as the analyte. Ligand density is set high enough to read a low mass analyte.

  • amine coupling
  • capture
  • ligand density

Deactivation

Unused activated sites are capped before the first compound arrives.

Without it the surface keeps reacting with whatever passes over, and non-specific binding shows up in the trace as signal unrelated to the pair being measured. The response then settles at the immobilised amount.

  • deactivation
  • blocking
  • non-specific binding

Association

The compound flows across the surface and the response climbs.

Sample and running buffer are matched so the bulk signal does not swamp the binding, and a reference channel removes what remains. Flow rate sets contact time, and the rising phase gives the on-rate, kon.

  • solvent matching
  • referencing
  • kon

Dissociation

Buffer replaces the sample and the response falls as the complex comes apart.

The falling phase gives the off-rate, koff, and 1/koff is residence time. A concentration series yields kon, koff, and KD. Where dissociation is too fast to fit, injection plateaus give steady-state affinity. With little material, single-cycle kinetics runs the series uninterrupted.

  • residence time
  • koff
  • KD
  • steady state
  • SCK

Regeneration

A regeneration buffer strips bound compound and returns the sensor to baseline.

The immobilised target stays in place, so every compound meets the same surface. Inject, read, regenerate, repeat, unattended. Every sensor on the chip reads each injection, so one sample can cover several targets, mutants, or controls.

  • regeneration
  • automated cycling
  • counter-screen
Response (RU) Time

What inQuiQ does for small molecule and peptide research

Six capabilities, one modular benchtop instrument, in a label-free workflow.

Many targets, one small sample

Flexibly addressable channels for improved assay freedom, with 16 sensors to screen mutants, off-targets and controls efficiently.

16 sensors (spotter required) 30 µL

Resolve low mass binders

Baseline noise stays low enough that a fragment-sized mass change is still readable.

0.1 RU RMS

Cover fragment hits through to optimised leads

Measure mM fragment binding and pM lead binding on one instrument. If binding is too fast to fit kinetics, KD comes from steady-state analysis.

10 pM to 10 mM

Confirm mechanism alongside potency

Competitive assays show whether two compounds share a site, and a dose response gives IC50 or EC50 on the same surface.

IC50 EC50

Add thermodynamic detail

The temperature-controlled flow cell runs a full temperature series.

temp. control from 16 to 40 °C

Modular system for an increased throughput

Simply add an autosampler, and increasy your throughput for library screens.

2×96 wells 2×384 wells
Start A conversation

See inQuiQ run your compound analysis

Tell us your target, your compound class, and the binding questions you need answered. We will show you inQuiQ on an assay close to yours.

Ready to see the inQuiQ in action?

Questions researchers ask

Immobilise the target protein on the sensor, then inject a concentration series of the compound. inQuiQ records association and dissociation in real time and fits the data to give affinity (KD) and kinetics (kon, koff) across a range of 10 pM to 10 mM. Weak binders are fitted at steady state instead.

Yes, as long as the sensor resolves the small mass change a fragment produces. inQuiQ runs at a baseline noise of 0.1 RU RMS, and ligand density is set high enough that a fragment under 300 Da gives a readable response. Weak binding is then fitted at steady state.

Residence time is the average time a compound stays bound, calculated as 1 divided by the off-rate (koff). inQuiQ measures koff directly from the dissociation phase in real time, so two compounds with the same IC50 can still be separated by how long each one holds its target.

Immobilise the protein partner and inject the peptide as a concentration series, or capture the peptide and flow the protein past. inQuiQ records association and dissociation in real time, returning kon, koff, and KD. The inQuiQ can handle most buffers, like DMSO, which is useful for small molecule work.

The rule of 3 is a guideline for fragment libraries: molecular weight under 300 Da, no more than three hydrogen bond donors, no more than three acceptors, and a cLogP of three or less. Fragments this small bind weakly, so screening needs a method sensitive to a small mass change.

Compound stocks dissolved in DMSO can be injected directly. Match the DMSO percentage between running buffer and sample, so the bulk refractive index signal stays flat across the concentration series and the binding response is not masked by a solvent mismatch.