Description
Surface-functional biosensor recognition ligand designed for selective detection of Amyloid Beta 42 (Aβ42), 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 and microfluidic biosensor platforms. For Research Use Only (RUO).
Product Description
The ProbeSeq Amyloid Beta 42 BiosensorProbe™ is a carboxyl-functionalized single-stranded DNA aptamer engineered for selective recognition and capture of amyloid beta 42 peptide, a neurotoxic aggregation-prone peptide widely used as a biomarker for Alzheimer’s disease diagnosis and progression 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.
Amyloid beta 42 is a 42-amino-acid peptide (~4.5 kDa) derived from amyloid precursor protein (APP) and forms oligomers and plaques associated with neurodegeneration. Plasma concentrations typically range from 10–100 pg/mL, with altered levels associated with Alzheimer’s pathology. The BiosensorProbe™ supports ultrasensitive detection across clinically relevant concentration ranges.
The probe enables stable covalent surface attachment, controlled probe orientation, and high surface density (~10¹² molecules/cm²) for reproducible biosensor performance.
Recognition Mechanism
Target recognition is mediated by a sequence-engineered single-stranded DNA aptamer (~40–75 nucleotides) forming a selective three-dimensional structure that recognizes Aβ42 monomeric and oligomeric conformations through hydrogen bonding and structural complementarity.
Binding affinity (Kd): 0.02–0.8 nM
Detection range: pg/mL to ng/mL
Association kinetics: seconds to minutes
Selective recognition of Aβ42 vs Aβ40 isoform
Specificity and Selectivity
The Aβ42 BiosensorProbe™ demonstrates strong selectivity toward Aβ42 with minimal cross-reactivity toward Aβ40 and unrelated neuronal proteins.
Cross-reactivity: <5% vs Aβ40
Non-specific adsorption reduction: >90%
Matrix compatibility: plasma, serum, cerebrospinal fluid
Molecular Format and Functionalization
Synthetic single-stranded DNA aptamer containing terminal carboxyl functional group.
Aptamer length: ~40–75 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.
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
High stability under flow conditions
Compatible Sensor Surfaces
Amine-functionalized polymer surfaces
Aminated graphene and carbon electrodes
Silicon oxide and glass substrates
Microfluidic polymer chips
Hydrogel biosensors
Paper-based analytical devices
Performance Characteristics
Binding affinity: 0.02–0.8 nM
Surface coverage: ~10¹² molecules/cm²
Operating temperature: 4–45°C
Low probe desorption
Stable signal response
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
Alzheimer’s disease diagnostics research
Neurodegeneration monitoring
Amyloid aggregation studies
Drug screening platforms
Electrochemical biosensor development
Microfluidic neurological diagnostics
