Poly‐ε‐Lysine Modified Nanocarbon Film Electrodes for LPS Detection

Abstract

We developed an electrochemical system for detecting lipopolysaccharide (LPS) that uses an ultraflat nanocarbon film electrode modified with poly‐ε‐lysine with a high affinity to LPS. LPS was captured on the modified electrode, and then ferrocene labeled polymyxin B (FcPMB) was captured on the LPS adsorbed electrode via the LPS‐PMB affinity interaction. The adsorbed FcPMB provided an amplified response with Fe2+ ions, and the current response was dependent on the amount of captured LPS (LOD=2.0 ng/mL). This was due to the efficient accumulation of the obtained current for LPS and the very low noise made possible by the ultraflat surface.

Methods of Endotoxin Detection

“…57 Thompson et al 58 published preliminary research on a real-time and label-free detection of LPS in human whole-blood plasma using ultra-high-frequency acoustic wave sensing in PmB-modified piezoelectric quartz discs. Kato et al 59 used ferrocene-labeled PmB as a signal probe, which was captured by a poly-epsilon-lysine-modified ultraflat nanocarbon film electrode. The detection limit of LPS was achieved to 2 ng/mL.…”

“…The detection limit of LPS was achieved to 2 ng/mL. 59 Ferrocene-labeled PmB was also employed to construct an enzymatically amplified electrochemical biosensor to detect LPS as low as 50 ng/mL within 5 min. 60…”

“…The detection limit of LPS was achieved to 2 ng/ mL. 59 Ferrocene-labeled PmB was also employed to construct an enzymatically amplified electrochemical biosensor to detect LPS as low as 50 ng/mL within 5 min. 60 Two peptide variants derived from CD14 were fluorescently labeled and applied to detect and discriminate LPS down to the submicromolar concentration range.…”

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

“…The high positive charge on the PmB helps to neutralize the toxicity of LPS. The polycationic molecule PmB has high affinity toward LPS 19 with an equilibrium association constant of ∼2.5 × 10 6 M −1 . 20 Herein, we chose PmB as the LPS binding molecule on the electrode surface.…”

High-throughput living cell-based optical biosensor for detection of bacterial lipopolysaccharide (LPS) using a red fluorescent protein reporter system

“…These methods depend on selection of a recognition element, especially a bio-receptor or ligand. Several systems have been reported for the detection of LPS that use anti-LPS antibodies8 or antibiotics such as Polymyxin B91011, and molecules designed specifically for LPS neutralization, namely aptamers121314, LPS binding proteins1516171819 or peptides2021, and other synthetic LPS recognizing molecules22232425 as the recognition element. In addition to using natural and synthetic molecules with LPS affinity, living cells to detect LPS have been designed726.…”