Description
Surface-functional biosensor recognition ligand designed for selective detection of Glial Fibrillary Acidic Protein (GFAP), supplied as a thiol-modified DNA aptamer for direct immobilization on gold and thiol-reactive sensor surfaces. Engineered for high binding specificity, controlled probe orientation, and stable integration into electrochemical and microfluidic biosensor platforms. For Research Use Only (RUO).
Product Description
The ProbeSeq Glial Fibrillary Acidic Protein BiosensorProbe™ is a thiol-functionalized single-stranded DNA aptamer engineered for selective recognition and capture of GFAP, a structural intermediate filament protein expressed in astrocytes and widely used as a biomarker for traumatic brain injury, stroke, neurodegeneration, and neurological disease monitoring. The probe incorporates a terminal sulfhydryl (–SH) functional group enabling stable covalent immobilization on gold sensor interfaces while preserving aptamer folding and binding activity.
GFAP is a cytoskeletal protein (~50 kDa) released into circulation following astrocyte injury and blood–brain barrier disruption. Baseline serum levels are typically <0.02 ng/mL and may increase to >0.1–10 ng/mL following brain injury depending on severity. The BiosensorProbe™ supports ultrasensitive detection across clinically relevant concentration ranges.
The probe enables high-density surface immobilization (~10¹²–10¹³ molecules/cm²), controlled probe orientation, and stable signal generation across electrochemical, impedance, and optical sensing platforms.
Recognition Mechanism
Target recognition is mediated by a sequence-engineered single-stranded DNA aptamer (~45–85 nucleotides) forming a high-affinity binding structure specific to GFAP epitopes through hydrogen bonding, electrostatic interactions, and structural complementarity.
Binding affinity (Kd): 0.02–1 nM
Detection range: pg/mL to ng/mL
Association kinetics: seconds to minutes
Reversible binding suitable for quantitative monitoring
Specificity and Selectivity
The GFAP BiosensorProbe™ demonstrates high specificity toward GFAP with minimal cross-reactivity toward other neuronal injury markers including S100β, UCH-L1, and neurofilament proteins.
Cross-reactivity: <3% against related neural proteins
Non-specific adsorption reduction: >90% vs non-functionalized DNA
Matrix compatibility: serum, plasma, cerebrospinal fluid, and whole blood extracts
Molecular Format and Functionalization
Synthetic single-stranded DNA aptamer containing terminal thiol functional group.
Aptamer length: ~45–85 nucleotides
Functionalization efficiency: ≥95% thiol incorporation
Purity: ≥95% (HPLC verified)
End modification: 5′ C6-thiol linker
Buffer formulation: nuclease-free buffered solution
Surface Immobilization Chemistry
Terminal thiol enables self-assembled monolayer formation on gold surfaces via Au–S bonding.
Surface binding strength: ~40–50 kcal/mol
Immobilization time: 30–120 min
Recommended surface density: 1–10 pmol/cm²
Operating pH after immobilization: 6.5–8.5
Compatible Sensor Surfaces
Gold electrodes and nanostructured gold substrates
Gold nanoparticle-modified interfaces
Thiol-reactive polymer coatings
Maleimide-functionalized surfaces
Electrochemical biosensors
Microfluidic diagnostic devices
Wearable neurological monitoring systems
Performance Characteristics
Binding affinity: 0.02–1 nM
Surface coverage: 10¹²–10¹³ molecules/cm²
Operating temperature: 4–45°C
Low non-specific adsorption
Stable signal response during repeated measurement cycles
Stability
Shelf stability: ≥12 months at −20°C
Working stability after immobilization: ≥14 days
Thermal tolerance: stable up to ~60°C short exposure
Storage
Store at −20°C in supplied buffer. Avoid repeated freeze–thaw cycles. Protect from oxidation and light.
Applications
Traumatic brain injury detection
Concussion monitoring systems
Stroke biomarker detection
Neurodegeneration research
Electrochemical biosensor development
Microfluidic neurological diagnostics
