Fragments and covalent fragment screening
Detect binding of fragments under 300 Da.
Confirm that a fragment binds at all.
weak binders
Label-free small molecule binding kinetics for fragment-based drug discovery
Fragments, inhibitors, and peptides binding affinity and kinetics. The inQuiQ resolves the weak and short-lived binding that fragment-based drug discovery runs on, in real time and on your own bench.
Fragment-based drug discovery, inhibitors, peptides and modulators
Every compound class brings its own binding question. inQuiQ answers them from one platform.
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
Peptide binding assays
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
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 RMSka, kd, 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.
competitive assaysIC50, EC50
blocked, or bound alongside
How a small molecule binding assay 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.
Immobilization
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, fragment library screening and a peptide binding assay, with the compound injected as the 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 immobilized 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, ka.
- solvent matching
- referencing
- ka
Dissociation
Buffer replaces the sample and the response falls as the complex comes apart.
The falling phase gives the off-rate, kd, and 1/kd is residence time. A concentration series yields ka, kd, 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
- kd
- KD
- steady state
- SCK
Regeneration
A regeneration buffer strips bound compound and returns the sensor to baseline.
The immobilized 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 fragment-based drug design 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 optimized leads
Measure mM fragment binding and pM lead binding for fragment-based lead discovery. Fast binding yields KD by steady-state analysis.
10 pM to 10 mM
Confirm mechanism alongside potency
Competitive assays show whether compounds share a site, while dose response supports IC50 determination.
4 channels
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 increase your throughput for library screens.
2×96 wells
2×384 wells
Explore the inQuiQ768
Application notes, publications, and data
From small molecule kinetics to antibody affinity, explore real binding data generated on inQuiQ. Each application note pairs a sensorgram with the affinity and kinetic values behind it.
Start A conversation
See inQuiQ run your small molecule or peptide binding assay
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?
Talk to an application scientist
Thirty minutes to discuss your assay design, before anyone mentions an instrument.
Download the inQuiQ brochure
Sensitivity, channel layout, footprint, and consumable formats in a couple of pages.
Delta Life Science
request@deltalifescience.nl
Send us an email, and we will get back to you as soon as possible.
request@deltalifescience.nl
Send us an email, and we will get back to you as soon as possible.
Questions researchers ask
A small molecule binding assay starts by immobilizing the target protein on the sensor, then injecting a concentration series of the compound. The 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. The 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. Covalent fragment screening is read from the same trace: where a bond has formed the response holds through the dissociation phase, which is the readout covalent drug discovery depends on.
Residence time is the average time a compound stays bound, calculated as 1 divided by the off-rate (koff). The 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.
Immobilize the protein partner and inject the peptide as a concentration series, or capture the peptide and flow the protein past. The 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.