Electrochemical sensor with substitutional stripping voltammetry for highly sensitive endotoxin assay

Area of Science:

• Analytical Chemistry
• Biotechnology
• Biosensing

Background:

• Endotoxin detection is crucial for clinical and pharmaceutical safety.
• Existing methods for endotoxin detection often lack sufficient sensitivity or require complex procedures.
• The Limulus amebocyte lysate (LAL) cascade reaction is a standard for endotoxin testing.

Purpose of the Study:

• To develop a novel, highly sensitive method for endotoxin detection.
• To utilize substitutional stripping voltammetry (SSV) for enhanced endotoxin quantification.
• To demonstrate the efficacy of a p-aminophenol (pAP) conjugated peptide substrate in the LAL assay.

Main Methods:

• Developed a chip device with two connected cells for reaction and deposition.
• Employed p-aminophenol (pAP) conjugated peptide (Boc-Leu-Gly-Arg-pAP; LGR-pAP) as a substrate for protease in the LAL cascade.
• Utilized SSV, coupling amperometric signal accumulation with silver deposition and anodic stripping voltammetry (ASV) for quantification.

Main Results:

• Achieved extra-high sensitivity in endotoxin detection using the SSV method.
• Demonstrated a linear correlation between ASV signal and endotoxin concentration from 0.5 to 1000 EU L(-1).
• Successfully quantified liberated pAP, a product of the endotoxin-induced LAL reaction.

Conclusions:

• The developed SSV-based endotoxin assay provides a highly sensitive and reliable detection method.
• This novel approach offers a promising alternative for sensitive endotoxin quantification in various applications.
• The chip device integrates reaction and detection, simplifying the assay procedure.