Single-Molecule Discrimination and the Specific Binding Properties of the Lipopolysaccharides with a Solid-State Nanopore sensor

Abstract

Lipopolysaccharides (LPS) are the major constituent on the cell envelope of all gram-negative bacteria. They are ubiquitous in water, air, and food, and are toxic inflammatory stimulators and optimal biomarkers for some urinary disorders and sepsis. A good many optical, electrical, thermal, and electrochemical sensors based on the intermolecular interplay of LPS with proteins, peptides, and aptamers are reported, they are generally complicated methods. We demonstrate the single-molecule nanopore approach for the identification of LPS from distinct bacteria as well as the discrimination of serotypes from the same bacterium. With a 4 nm nanopore, we achieve a LOD of 10 ng/mL and a linear response up to 10,000 ng/mL. Both the antibiotic PMB and DNA aptamer display good binding affinity to LPS, and the complexes exhibit distinct nanopore translocation behaviors compared with the individual LPS. The real sample tests in both human serum and tap water show good performance characteristics in the identification of LPS in complicated media with a nanopore platforms. Our work shows a highly-sensitive and easy-to-handle scheme for clinical and environmental biomarkers determination and provides a promising screening tool for early warning of contamination in food, water, and medical supplies.