The Science
Why the monomer is the molecule that matters
C-reactive protein has two faces. Understanding the difference is the whole point of our platform.
The biology of CRP
One protein, two very different behaviours
CRP is produced by the liver and circulates as a stable, disc-shaped pentamer (pCRP) — a general, largely inactive marker that rises hours to days after an inflammatory stimulus. At sites of tissue injury and inflammation, pCRP dissociates on activated cell membranes into five monomers (mCRP). This monomeric form is the biologically active species: it is largely insoluble, tissue-bound, and strongly pro-inflammatory, promoting platelet activation, endothelial dysfunction, complement engagement, and leukocyte recruitment.
Because standard assays report the circulating pentamer, they capture the reservoir of inflammation, not the action. Measuring mCRP directly aims to localise the signal to where inflammation is actually doing its work.
In short
The Sentos binder
A synthetic aptamer raised against native human mCRP
Aptamers are short, single-stranded DNA or RNA sequences that fold into precise three-dimensional shapes and bind a target with antibody-like specificity. The Sentos binder is a DNA aptamer selected (via SELEX) against native human mCRP and characterised by surface plasmon resonance.
| Parameter | Sentos binder |
|---|---|
| Binding affinity (KD) | 1.51 × 10⁻⁷ M (≈151 nM) |
| Association rate (ka) | 4.24 × 10³ M⁻¹s⁻¹ |
| Dissociation rate (kd) | 6.41 × 10⁻⁴ s⁻¹ |
| mCRP vs pCRP discrimination | >95% specificity TODO: Supported |
| Format | Chemically synthesised DNA |
| Robustness | Stable through repeated binding/regeneration cycles in SPR characterisation |
Reproducible
chemical synthesis gives batch-to-batch consistency, without animal-derived variability.
Robust
greater thermal tolerance than antibodies — relevant for distribution in warm climates.
Economical
scalable synthesis supports a favourable cost structure at volume.
The method: competitive ALISA
Aptamer-Linked Immuno-Sorbent Assay (ALISA)
The mCRP-ALISA™ is a competitive assay. mCRP immobilised on the microplate competes with mCRP in the patient sample for a fixed amount of the biotin-labelled Sentos binder. The more mCRP in the sample, the less aptamer binds the plate — so the colorimetric signal (streptavidin-HRP / TMB) is inversely proportional to sample mCRP concentration.
- 1Patient serum is added to an mCRP-coated microplate alongside the biotinylated Sentos binder.
- 2Sample mCRP and plate-bound mCRP compete for the aptamer.
- 3Unbound material is washed away; streptavidin-HRP and TMB substrate develop colour.
- 4Signal is read colorimetrically; lower signal indicates higher sample mCRP.
| Parameter | Current performance |
|---|---|
| Limit of detection | Approximately 100 ng/mL |
| Specificity (mCRP vs pCRP) | >95% discrimination |
| Sample type | Human serum |
| Readout | Colorimetric (TMB), microplate |
| Cross-reactivity | <5% vs pCRP; <1% vs albumin |
Origin of the science
From doctoral research to a company
The Sentos binder and the ALISA method originate in the doctoral research of Dr. Revathy Munuswamy, PhD. Sentos BioMed was founded to translate that research into a validated, manufacturable diagnostic platform, with operations in Chennai.