Description
Surface-functional biosensor recognition ligand designed for selective detection of N-Terminal pro-B-Type Natriuretic Peptide (NT-proBNP), supplied as a thiol-modified DNA aptamer for direct immobilization on gold and thiol-reactive sensor surfaces. Engineered for controlled probe orientation, high binding specificity, and stable integration into electrochemical and microfluidic biosensor platforms. For Research Use Only (RUO).
Product Description
The ProbeSeq NT-proBNP BiosensorProbe™ is a thiol-functionalized single-stranded DNA aptamer engineered for selective recognition and capture of NT-proBNP, a clinically established biomarker used for diagnosis, prognosis, and monitoring of heart failure and cardiovascular dysfunction. The probe incorporates a terminal sulfhydryl (–SH) functional group enabling controlled covalent immobilization on gold and thiol-reactive sensor interfaces while preserving aptamer folding and target-binding activity.
NT-proBNP is a 76–amino acid peptide fragment (~8.5 kDa) released during cleavage of proBNP from cardiomyocytes under cardiac stress conditions. Physiological plasma levels typically range from <125 pg/mL in healthy individuals and may exceed >1000 pg/mL in heart failure patients. The BiosensorProbe™ enables sensitive surface-based detection across clinically relevant concentration ranges.
The probe is optimized for surface-immobilized sensing environments, enabling dense probe packing (~10¹²–10¹³ molecules/cm² on gold surfaces), controlled orientation, and stable signal generation across electrochemical, optical, and impedance-based detection platforms.
Recognition Mechanism
Target recognition is mediated by a sequence-engineered single-stranded DNA aptamer (~40–75 nucleotides) that undergoes conformational folding upon interaction with NT-proBNP structural epitopes. Binding occurs through electrostatic interactions, hydrogen bonding, and molecular shape complementarity.
Typical equilibrium dissociation constant (Kd): 0.5–5 nM
Association kinetics: rapid binding within seconds to minutes
Detection capability: pg/mL to ng/mL range depending on sensor platform
The aptamer provides reversible binding suitable for quantitative biosensing and continuous cardiac monitoring applications.
Specificity and Selectivity
The NT-proBNP BiosensorProbe™ demonstrates high molecular specificity toward NT-proBNP with minimal cross-reactivity toward BNP, ANP, and other circulating natriuretic peptides.
Cross-reactivity: <3% against BNP and ANP
Non-specific adsorption reduction: >90% compared to non-functionalized DNA controls
Matrix compatibility: serum, plasma, and whole blood extracts
Sequence-driven recognition targets unique NT-proBNP peptide epitopes, enabling selective detection in complex biological samples.
Molecular Format and Functionalization
Synthetic single-stranded DNA aptamer containing terminal thiol (–SH) functional group introduced via controlled chemical modification.
Aptamer length: ~40–75 nucleotides
Functional group incorporation: ≥95% thiol modification
Purity: ≥95% (HPLC verified)
End modification: 5′ or 3′ thiol linker (C6 or equivalent)
The probe is chemically stabilized to preserve structural folding and functional group reactivity.
Surface Immobilization Chemistry
The terminal thiol group supports direct immobilization on gold electrodes through formation of self-assembled monolayers via Au–S bonding.
Surface binding strength: ~40–50 kcal/mol Au–S interaction
Typical immobilization time: 30–120 min
Recommended surface density: 1–10 pmol/cm²
Operating pH range after immobilization: 6.5–8.5
Compatible with nanostructured gold, planar gold electrodes, gold nanoparticles, and maleimide-functionalized surfaces.
Compatible Sensor Surfaces
Gold electrodes and nanostructured gold substrates
Gold nanoparticle-modified interfaces
Thiol-reactive polymer coatings
Maleimide-functionalized surfaces
Electrochemical impedance and amperometric sensors
Microfluidic lab-on-chip platforms
Wearable cardiac monitoring devices
Performance Characteristics
Binding affinity (Kd): 0.5–5 nM
Surface coverage: 10¹²–10¹³ molecules/cm²
Operating temperature range: 4–45°C
Low non-specific adsorption on gold surfaces
Stable signal response over repeated measurement cycles
Stability
The NT-proBNP BiosensorProbe™ is chemically stabilized to maintain aptamer conformation and thiol reactivity.
Shelf stability: ≥12 months at −20°C
Working stability after immobilization: ≥7–14 days depending on surface conditions
Thermal stability: stable up to ~60°C for short exposure
Storage
Store at −20°C in supplied buffered formulation (10 mM Tris, 1 mM EDTA, pH 7.4 or equivalent). Avoid repeated freeze–thaw cycles and prolonged exposure to oxidizing conditions. Store protected from light.
Applications
Heart failure biomarker detection
Cardiovascular diagnostics research
Electrochemical biosensor development
Point-of-care cardiac monitoring systems
Microfluidic diagnostic devices
Multiplex cardiovascular panels
Wearable cardiac sensing platforms
