Voltammetric Detection of Cadaverine with DAO-MWCNT Electrochemical Biosensor

Vocabulary flashcards covering key terms, materials and analytical concepts from the lecture notes on the DAO-MWCNT voltammetric biosensor for cadaverine detection.

Cadaverine

A biogenic polyamine (1,5-pentanediamine) linked to food spoilage and periodontal disease; target analyte in the study.

Polyamines

Small, positively charged molecules (e.g., cadaverine, putrescine) formed by amino-acid decarboxylation and implicated in inflammation.

Diamine Oxidase (DAO)

An enzyme that catalyzes oxidative deamination of primary diamines such as cadaverine, producing 5-aminobutanal and H₂O₂.

Multi-Walled Carbon Nanotubes (MWCNTs)

Cylindrical carbon nanostructures with multiple concentric graphene layers; provide high surface area and fast electron transfer for biosensors.

Screen-Printed Electrode (SPE)

Disposable electrode fabricated by printing conductive inks onto a substrate; used as the biosensor platform.

Cyclic Voltammetry (CV)

Electrochemical technique where potential is cycled to record current, revealing redox peaks of analytes.

Differential Pulse Voltammetry (DPV)

Pulse-based voltammetric method offering enhanced sensitivity; used to construct the cadaverine calibration curve.

Carbodiimide Crosslinking

Chemistry that activates carboxyl groups to form amide bonds with amines, enabling covalent enzyme attachment.

EDC (1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide)

Water-soluble carbodiimide reagent that activates –COOH groups on MWCNTs for coupling to DAO.

NHS (N-Hydroxysuccinimide)

Stabilizer that reacts with EDC-activated carboxyls to create semi-stable esters, improving coupling efficiency.

Glutaraldehyde (GA)

Bifunctional aldehyde used as an additional crosslinker to strengthen DAO immobilization on the electrode.

Limit of Detection (LOD)

Lowest analyte concentration that can be reliably distinguished from blank; 0.8 µg mL⁻¹ for cadaverine in this study.

Electrochemical Biosensor

Analytical device combining a biological recognition element with an electrochemical transducer to generate an electrical signal.

Carboxylation (of MWCNTs)

Acid treatment introducing –COOH groups onto nanotube surfaces to enable covalent enzyme attachment.

Energy-Dispersive X-ray Spectroscopy (EDX)

Surface analysis technique that determines elemental composition of electrode before and after modification.

Fourier Transform Infrared Spectroscopy (FTIR)

Spectroscopic method that identifies functional groups; confirmed formation of amide bonds on modified MWCNTs.

Britton–Robinson Buffer

Universal buffer (pH 2–12) composed of phosphoric, acetic and boric acids; used as supporting electrolyte.

Artificial Saliva

Laboratory formulation mimicking human saliva, employed to test biosensor performance in a realistic matrix.

Technology Readiness Level (TRL)

Scale indicating maturity of technology; testing in artificial saliva raised the biosensor’s TRL.

Physical Adsorption

Non-covalent enzyme immobilization via electrostatic forces; simple but can orient enzymes unfavorably.

Covalent Immobilization

Stable attachment of biomolecules to a surface through chemical bonds, enhancing sensor lifetime and response.

Periodontitis

Inflammatory gum disease associated with elevated cadaverine; target clinical application for the biosensor.