Description
Surface-functional biosensor recognition ligand designed for selective detection of Glial Fibrillary Acidic Protein (GFAP), supplied as a carboxyl-modified DNA aptamer for covalent immobilization onto amine-functionalized sensor surfaces using EDC/NHS chemistry. Engineered for stable probe orientation, high binding specificity, and long-term integration into electrochemical, optical, and microfluidic biosensor platforms. For Research Use Only (RUO).
Product Description
The ProbeSeq Glial Fibrillary Acidic Protein BiosensorProbe™ is a carboxyl-functionalized single-stranded DNA aptamer engineered for selective recognition and capture of GFAP, a structural astrocytic protein widely used as a biomarker for traumatic brain injury, stroke, and neurodegenerative disease monitoring. The probe incorporates a terminal carboxyl (–COOH) functional group enabling covalent amide bond formation with primary amine-functionalized sensor surfaces via carbodiimide (EDC/NHS) activation.
GFAP is an astrocyte-specific intermediate filament 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 neurological injury. The BiosensorProbe™ enables ultrasensitive detection across clinically relevant concentration ranges.
The probe supports stable covalent surface attachment, high probe density (~10¹² molecules/cm²), and robust signal reproducibility across biosensor platforms requiring long-term stability.
Recognition Mechanism
Target recognition is mediated by a sequence-engineered single-stranded DNA aptamer (~45–85 nucleotides) forming a selective three-dimensional binding structure that recognizes GFAP epitopes via hydrogen bonding, electrostatic interactions, and conformational 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 neuronal injury markers including S100β, UCH-L1, and tau 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 carboxyl functional group.
Aptamer length: ~45–85 nucleotides
Functionalization efficiency: ≥95% COOH incorporation
Purity: ≥95% (HPLC verified)
End modification: 5′ C6-carboxyl linker
Buffer formulation: nuclease-free buffered solution
Surface Immobilization Chemistry
Carboxyl group enables covalent amide bond formation with amine-functional surfaces using carbodiimide coupling.
Activation chemistry: EDC/NHS coupling
Coupling efficiency: >85%
Bond type: covalent amide linkage
Immobilization time: 20–60 min
Operating pH after immobilization: 6.0–8.0
Highly stable attachment under flow and repeated measurements
Compatible Sensor Surfaces
Amine-functionalized polymer surfaces
Aminated graphene and carbon electrodes
Silicon oxide and glass surfaces
Microfluidic polymer chips (COC, PMMA, PDMS after amination)
Hydrogel-based biosensors
Paper-based analytical devices
Performance Characteristics
Binding affinity: 0.02–1 nM
Surface coverage: ~10¹² molecules/cm²
Operating temperature: 4–45°C
High mechanical and chemical stability
Low probe desorption under continuous flow
Stability
Shelf stability: ≥12 months at −20°C
Working stability after immobilization: ≥21 days
Resistant to shear and washing cycles
Storage
Store at −20°C in supplied buffer. Avoid repeated freeze–thaw cycles. Protect from light.
Applications
Traumatic brain injury detection
Concussion monitoring
Stroke biomarker detection
Wearable neurological sensors
Microfluidic biosensor platforms
Surface-functional biosensor development
