Description
Surface-functional biosensor recognition ligand designed for selective detection of Epidermal Growth Factor Receptor (EGFR), 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 Epidermal Growth Factor Receptor BiosensorProbe™ is a thiol-functionalized single-stranded DNA aptamer engineered for selective recognition and capture of EGFR, a membrane-associated receptor tyrosine kinase widely used as a biomarker for cancer diagnosis, prognosis, and targeted therapy monitoring. 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.
EGFR is a transmembrane glycoprotein receptor (~170 kDa) involved in cell proliferation and signaling pathways and is frequently overexpressed in lung, colorectal, head and neck, and glioblastoma cancers. Circulating EGFR extracellular domain concentrations typically range from 10–50 ng/mL in serum and may increase significantly in cancer progression. The BiosensorProbe™ enables sensitive 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 (~40–80 nucleotides) that undergoes conformational folding upon interaction with EGFR extracellular domain epitopes. Binding occurs through electrostatic interactions, hydrogen bonding, and molecular shape complementarity.
Typical equilibrium dissociation constant (Kd): 0.1–5 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 real-time monitoring.
Specificity and Selectivity
The EGFR BiosensorProbe™ demonstrates high molecular specificity toward EGFR with minimal cross-reactivity toward HER2, HER3, and other ErbB receptor family members.
Cross-reactivity: <5% against related receptor proteins
Non-specific adsorption reduction: >90% compared to non-functionalized DNA controls
Matrix compatibility: serum, plasma, cell lysates, and extracellular vesicle samples
Sequence-driven recognition enables selective detection in complex biological matrices.
Molecular Format and Functionalization
Synthetic single-stranded DNA aptamer containing terminal thiol (–SH) functional group introduced via controlled chemical modification.
Aptamer length: ~40–80 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
Liquid biopsy sensing platforms
Performance Characteristics
Binding affinity (Kd): 0.1–5 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 EGFR 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
Cancer biomarker detection
Targeted therapy monitoring
Liquid biopsy research
Electrochemical biosensor development
Microfluidic diagnostic devices
Oncology biomarker panels
Extracellular vesicle analysis
