Layer-by-Layer Assembly of Polycations and Polyanions for the Sensitive Detection of Endotoxin

Abstract

Bacterial endotoxin detection is an essential safety requisite in biomedical, food, and pharmaceutical industries. Endotoxin in a sufficient concentration on entering the human bloodstream causes detrimental effects such as septic shock, which can lead to death. Hence, the sensitive and selective detection of endotoxin also known as lipopolysaccharide (LPS) is of paramount importance. Herein, a layer-by-layer (LBL) assembly of goldchitosan nanocomposite (CGNC)−poly(acrylic acid) (PAA)− polymyxin B (PmB) on gold (Au) electrode is employed for the sensitive and selective detection of endotoxin. The surface electric charge studies using dynamic contact mode electrostatic force microscopy (DC-EFM) revealed the successful formation of each layer on the Au electrode. The polycationic PmB is a specific bioreceptor of LPS, which binds with high affinity to the anionic groups of the carbohydrate portions of LPS molecules and facilitates the selective electrochemical detection. This surface modification method presented a sensitive and selective detection of endotoxin down to the attogram level.

Electrochemical Approach for the Synthesis of Ultrasmall Cu13 Clusters and Their Application in the Detection of Endotoxin

“…Polymyxin B (PmB) is another LPS-binding molecule with antibacterial properties, which will bind with LPS and neutralize its toxic effects. There are reports on LPS detection using PmB as a bioreceptor. , …”

Label-Free Resonance Rayleigh Scattering Amplification for Lipopolysaccharide Detection and Logical Circuit by CRISPR/Cas12a-Driven Guanine Nanowire Assisted Non-Cross-Linking Hybridization Chain Reaction

“…Fortunately, Kim et al selected the highest affinity aptamer instead of antibodies for specific recognition of LPS and provided an alternative method, aptasensor, for LPS detection . In this case, vast endeavors have focused on developing various aptasensors for LPS detection. − Nevertheless, the currently reported aptasensors are still not sensitive enough to meet the demand for trace LPS detection. This might be attributed to several factors, such as the complicated labeling of the signal molecule on the aptamer probe and without efficient signal amplification.…”

Multiarchitecture-Based Plasmonic-Coupled Emission Employing Gold Nanoparticles: An Efficient Fluorescence Modulation and Biosensing Platform

“…Gold nanoparticles (AuNPs) possess particular physical and chemical properties, such as high stability, good compatibility, and easy surface functionalization, which make them ideal materials for a wide range of optical, chemical, biological, and clinical applications. − Among the different optical materials, AuNPs are the most popular candidate for the development of systems with high sensitivity and detection efficiency. , When metallic NPs interact with light, resonance energy coupling known as localized surface plasmon resonance (LSPR) can be evoked to create an intense electromagnetic (EM) field. LSPR occurs due to the energy transfer from the excited light to the collective oscillation of free electrons around the nanoparticles, which leads to a strong absorption of optical energy. − The absorption peak depends on the size, shape, aggregation state, and dielectric environment .…”

“…1−6 Among the different optical materials, AuNPs are the most popular candidate for the development of systems with high sensitivity and detection efficiency. 7,8 When metallic NPs interact with light, resonance energy coupling known as localized surface plasmon resonance (LSPR) can be evoked to create an intense electromagnetic (EM) field. LSPR occurs due to the energy transfer from the excited light to the collective oscillation of free electrons around the nanoparticles, which leads to a strong absorption of optical energy.…”