Biochip for the Detection of Bacillus anthracis Lethal Factor and Therapeutic Agents against Anthrax Toxins

Abstract

Tethered lipid bilayer membranes (tBLMs) have been used in many applications, including biosensing and membrane protein structure studies. This report describes a biosensor for anthrax toxins that was fabricated through the self-assembly of a tBLM with B. anthracis protective antigen ion channels that are both the recognition element and electrochemical transducer. We characterize the sensor and its properties with electrochemical impedance spectroscopy and surface plasmon resonance. The sensor shows a sensitivity similar to ELISA and can also be used to rapidly screen for molecules that bind to the toxins and potentially inhibit their lethal effects.

Membrane binding and pore formation is Ca2+-dependent for theClostridioides difficilebinary toxin

“…However, unlike what was found previously for other toxins, and verified here for anthrax PA (Fig. S1) ( 24, 25 ), CDTb did not bind lipid bilayers or form pores in membrane-like vesicles upon lowering pH to acidic values.…”

The Utility of Nanopore Technology for Protein and Peptide Sensing

“…It is often easier to detect proteins through an interaction outside the pore. One can take advantage of the natural binding affinity of AB toxins, such as the anthrax toxins, to devise a binding assay sensor . Rostovsteva and colleagues used a co‐localization assay to identify a likely sensor for the tubulin, which has disordered c‐terminal tails (CTT) that differ between isotypes.…”

Determining the Physical Properties of Molecules with Nanometer-Scale Pores

“…PA63 has been proven useful for both the detection of two other anthrax toxins (Lethal Factor and Edema Factor) with high sensitivity (ca. 40 pM) and screening for therapeutic agents against them. , Many studies have demonstrated reversible interactions between the N-terminus of Lethal Factor and Edema factor, − but under certain conditions the interaction becomes irreversible …”

“…40 pM) and screening for therapeutic agents against them. 87,88 Many studies have demonstrated reversible interactions between the N-terminus of Lethal Factor and Edema factor, 89−91 but under certain conditions the interaction becomes irreversible. 86 The MspA channel had to be modified for DNA sequencing applications (described above) because the native channel produces spontaneous ionic current blockades in the absence of single-stranded DNA, which would confound the characterization of nucleic acids.…”