An increase in endotoxin concentration in the bloodstream can trigger activation of innate immune response leading to septic shock. There is currently no method available for rapid endotoxin detection at a patient's bedside. We demonstrate a simple, portable and cost-effective strategy to measure endotoxin levels in human serum within 5min using a flow-through assay. A drop of serum containing LPS was spotted on an endotoxin-affinity membrane placed over high-wicking absorbent pads. Subsequent addition of polymyxin B sulfate drug-conjugated gold nanoparticles allowed concentration-dependent visualization of spots by the naked eye in the clinically-relevant range of 10pg/mL to 10ng/mL. The results were quantified using a concentration-calibrated color chart and the assay performance was tested with archival plasma samples of 18 known septicemia patients. The results showed a reasonably good correlation with the patients' hematological data. This proof-of-concept study puts forth an interesting alternative for early septicemia diagnosis in future.
Keywords: Endotoxin; Gold nanoparticle; Gram-negative bacteria; Lipopolysaccharide; Polymyxin B; Septicemia.
Copyright © 2017 Elsevier Inc. All rights reserved.