Endotoxin Detection Using Electrochemical Method and the Effect of Nanoscale Confinement
From LabAutopedia
Endotoxin Detection Using Electrochemical Method and the Effect
of Nanoscale Confinement
Srivatsa Aithal1, Gaurav Chatterjee1, Lilian Gong2, Sutapa Barua3, Kaushal Rege3 and Shalini Prasad1.
1Department of Electrical, Computer and Energy Engineering, Arizona State University, 2Wellsley College,
3Mechanical, Aerospace, Chemical and Materials Engineering, Arizona State University
Abstract:
The goal of this project is to design a nanotextured, electrical, label-free detection system for detection of low doses of endotoxins. Endotoxins are large, heat-stable lipopolysacchrides, which are the major component of cell walls of gram negative bacteria. Endotoxin detection have broad food safety and disease diagnostic application.
We have developed a label free electrochemical based endotoxin sensor, which detects the endotoxin using Electrochemical Impedance Spectroscopy. In electrochemical impedance spectroscopy the impedance between the electrodes at different frequency points is measured. This frequency response changes with the property of the nanolayers on the electrode, we use this property to detect endotoxin binding to the detector surface.Nanoporous alumina membranes which have been used in water filtration systems have been engineered to bind and detect endotoxins. We have designed a multi-scale architecture detection platform comprising of a base microelectronic platform on to which the nanoporous alumina membranes are overlaid. We have adopted layer-by-layer chemistry to immobilize endotoxins onto the detector surface. The endotoxin in the solution is immobilized on the surface of the electrode for detection using a sandwich of polymers PAA (anionic polymer)-and a cationic polymer. Various cationic polymers that have been synthesized have been evaluated to identify the polymer which demonstrates maximum affinity to endotoxins. These polymers are oppositely charged to that of the endotoxin which makes the endotoxon bind to the nanotextured alumina surface coated with the cationic polymer. The nanoporosity of the alumina membrane which was functionalized with these polymers contributes towards enhancing the sensitivity of detection. The increased sensitivity can be attributed to the increase in the surface area and increase in the number of binding sites within the membrane.
