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Endotoxin Activity Assay for the Detection of Whole Blood Endotoxemia in Critically Ill Patients
Published on: June 24, 2019
Determination of endotoxin through an aptamer-based impedance biosensor
Wenqiong Su1, Meng Lin, Hyuck Lee
1School of Chemical Engineering, Sungkyunkwan University, 440-746 Suwon, Republic of Korea.
Biosensors & Bioelectronics
|December 21, 2011
Summary
This study presents a new electrochemical biosensor for detecting lipopolysaccharide (LPS), a toxic impurity in biotherapeutics. The aptasensor offers sensitive and selective LPS detection in complex biological samples.
Area of Science:
- Biomedical Engineering
- Analytical Chemistry
- Molecular Biology
Background:
- Lipopolysaccharide (LPS), or endotoxin, is a toxic bacterial impurity found in recombinant protein therapeutics and plasmid DNA (pDNA) vaccines.
- Sensitive detection of LPS is crucial for biopharmaceutical safety, preventing adverse reactions like fever, hypotension, and shock.
- Existing detection methods may lack the sensitivity or specificity required for complex biological matrices.
Purpose of the Study:
- To develop a novel electrochemical biosensor for the sensitive and selective detection of lipopolysaccharide (LPS).
- To utilize a single-stranded DNA (ssDNA) aptamer as a specific recognition probe for LPS.
- To demonstrate the aptasensor's performance in terms of sensitivity, selectivity, and regenerability for practical applications.
Main Methods:
- An electrochemical biosensor was fabricated by immobilizing an LPS-specific ssDNA aptamer on a gold electrode surface using a 3-mercaptopropionic acid (MPA) linker.
- Electrochemical characterization was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to monitor surface modification.
- The aptasensor's response to varying LPS concentrations was measured, and its selectivity was tested against potential interfering substances.
Main Results:
- The aptamer exhibited high affinity to LPS with a dissociation constant (K(d)) of 11.9 nM.
- A linear relationship was observed between the charge-transfer resistance (ΔR(et)) and the logarithm of LPS concentration over a wide dynamic range (0.001-1 ng/ml).
- The aptasensor demonstrated high selectivity for LPS, even in the presence of pDNA, RNA, and bovine serum albumin (BSA), and was successfully regenerated under low pH conditions.
Conclusions:
- The developed electrochemical aptasensor provides a sensitive and selective method for detecting LPS.
- This biosensor offers a promising tool for monitoring LPS contamination in biopharmaceuticals and other complex biological samples.
- The regenerable nature of the aptasensor enhances its potential for routine analytical applications.
