Start with your markers
Send us the markers that matter, your sampling device and your expected volumes. Within one working day you will know which of them ISF can carry and what the volumes allow. A pilot is often the right first step here, and we will say when.
Not every marker list survives that check. Better to find out now than after the cohort is collected.
WHY interstitial fluid
Why interstitial fluid matters
We have validated dermal interstitial fluid biomarker quantification on the NULISA platform in direct partnership with Ascilion, a leader in dISF sampling technology.
Most biomarker work runs on plasma, serum or CSF, the well-established matrices conventional immunoassay platforms were designed around. But some of the most informative biology sits in matrices those platforms cannot handle, where ultra-sensitive detection and bespoke validation become the rate-limiting step.
Interstitial fluid is one of those matrices. ISF occupies the extracellular space surrounding cells. It is where cytokines signal, where chemokines recruit immune cells, and where soluble mediators carry information between tissue and circulation.
For decades, measuring those signals at tissue level meant punch biopsy: invasive, painful, scarring, and impractical for repeated or longitudinal sampling. Microneedle-based collection has changed that.
Unlike plasma, which dilutes local signal into systemic circulation, ISF gives direct access to the molecular state of the skin, or any tissue accessible by microneedle.
Inflammatory and immune-mediated skin disease
where local cytokine concentrations far exceed circulating ones.
Longitudinal monitoring
where repeated sampling matters more than the depth of any single sample.
Paediatric studies
where punch biopsy is ethically or practically problematic.
Cosmetics and dermocosmetics
where biopsy is not a viable product-development readout.
Tissue pharmacokinetics and target engagement
where drug levels at the site of action are the question.
Repeated measurement designs
including pre and post intervention and dose-response studies where biopsy cannot reliably be repeated.
the problem
The technical challenge
ISF samples are small, dilute and protein-poor compared with plasma. The cytokines and chemokines of interest typically sit in the femtogram to picogram-per-millilitre range, well below the limit of detection of conventional immunoassays.
Standard ELISA, multiplex bead arrays and conventional electrochemiluminescence platforms cannot resolve inflammatory signal in ISF without sample-concentration steps. Those steps introduce variability and consume material you often cannot spare.
Ultra-sensitive proteomics is a requirement here.
WHY interstitial fluid
Our validated ISF capability
We have validated dermal interstitial fluid biomarker quantification on the NULISA platform in direct partnership with Ascilion, a leader in dISF sampling technology.
Sampling
The validation used samples collected with Ascilion’s PELSA microneedle device.
Analysis
Samples were analysed on the NULISAseq™ Inflammation Panel 250 AQ, Alamar's absolute-quantitation 250-target inflammation panel.
Result
Strong analytical performance across cytokine and chemokine targets that conventional immunoassay platforms cannot resolve in this matrix.
And the wider picture on ISF detectability
Alamar's published detectability data puts interstitial fluid at 235 or more of the 250 targets on the Inflammation Panel 250, above 95%, and 105 or more of the 124 targets on the CNS Disease Panel 120, above 85%.
That makes ISF one of the best-performing alternative matrices on the platform, ahead of saliva, urine, nasal swabs, sputum and stool. For a matrix that until recently could not be analysed at all, that means avoiding the biopsy costs you almost nothing in detectability.
The partnership has also given us hands-on familiarity with device performance, sample-handling protocols and the matrix-specific validation requirements ISF imposes.
Simoa and MSD
what to use
Platforms for ISF biomarker work
What you can measure
Th1, Th2, Th17 and Th22 cytokines IL-4, IL-5, IL-13, IL-17A, IL-22, IL-31, IFN-γ, TNF-α and others
Chemokines CCL17/TARC, CCL22/MDC, CXCL8/IL-8, CXCL10/IP-10 and others
Soluble immune mediators and barrier proteins
Tissue pharmacokinetics drug concentrations at the site of action
Target engagement and pharmacodynamic markers
Custom biomarkers via NULISAqpcr™ or platform-specific custom development
Typical applications
Inflammatory skin disease
Atopic dermatitis, psoriasis, hidradenitis suppurativa and other inflammatory skin disease research.
Dermatology drug development
Biologic and small-molecule programmes, including pharmacodynamic and target-engagement biomarkers.
Cosmetics and dermocosmetics
Longitudinal repeated measurement, replacing or supplementing biopsy where biopsy was never a viable product-development readout.
Paediatric dermatology
Studies where biopsy is not appropriate.
Tissue pharmacokinetics
Dermatology and adjacent indications where drug concentration at the site of action is the endpoint.
Local versus systemic biology
Cross-referencing ISF signal against plasma from the same subject.
Sample requirements
Collection device: Ascilion PELSA recommended, as our validation used it. Other microneedle systems are fine, so let us know which at scoping.
Processing: None needed on site. Freeze as collected.
Aliquoting: Single-use aliquots.
Freeze and thaw: Keep cycles to a minimum: no more than 3 to 5 for NULISA (panel-dependent), 3 to 4 for Simoa, and 2 for MSD.
Storage: −80°C.
Shipping: On dry ice, with a manifest listing sample ID, volume, collection date, device and anatomical site.
How much do we need?
Send whatever the device collects, typically 1 to 5 µL. There’s no minimum volume.
At these volumes, samples almost always need diluting. Dilution behaves differently in ISF than in plasma, so we test it on your samples and confirm the usable volume at scoping. This is why ISF studies include a short feasibility step.
Keep the collection site consistent. The anatomical site affects results, so record it and use the same site for each person at every timepoint.
We confirm receipt and sample condition in writing within two working days, before anything is consumed.
Shipping samples internationally
We can arrange collection and shipping, or work with your preferred courier. Either way we confirm the logistics, temperature control and documentation at scoping, before any samples move.
Near-plasma insight, without a needle
Discuss your matrix with a scientist
Send us your matrix, volumes, sampling device and the markers that matter.
You will get a straight view on feasibility, platform and timeline before you commit anything, including a no where ISF cannot support the question.