High-sensitivity electrochemical aptasensor based on AuNPs/NH₂-UIO-66/PEI/MCNs nanocomposite for endotoxin detection

Endotoxins, specifically lipopolysaccharides (LPS), are components of the outer membrane of Gram-negative bacteria. Due to the fact that even extremely low concentrations of endotoxins can trigger the human body's inflammatory cascade, there is an urgent need to develop highly sensitive detection technologies for accurate identification and quantitative analysis of trace amounts of endotoxin. This study, based on an electrochemical sensing platform constructed using AuNPs/NH₂-UiO-66/PEI/MCNs functionalized nanocomposite materials, has successfully achieved efficient detection of endotoxins in food. Given the complex food matrix and numerous interfering substances, this sensor enhances its anti-interference capability through a multi-level cooperative interface design. It uses polyethyleneimine-modified mesoporous carbon nanospheres (PEI/MCNs) as the substrate and integrates the directional loading capability of NH₂-UIO-66 with the conductivity-enhancing effect of gold nanoparticles (AuNPs), thereby significantly improving signal stability. This biosensor achieves a remarkable detection limit as low as 40 fg/mL, enabling trace-level identification of LPS. Additionally, it exhibits excellent selectivity against common foodborne interferents, facilitating rapid and accurate LPS detection.This study presents a novel, portable detection solution for the rapid screening of microbial contamination in food. The nanocomposite interface construction strategy employed herein provides significant guidance for developing trace-level hazard detection technologies in complex matrices.