title: In vitro flow-through assay for rapid detection of endotoxin in human sera: A proof-of-concept.
abstract: 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.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, India.
authors.forename: Prasanta
authors.initials: P
authors.lastname: Kalita
authors.affiliation: Molecular Diagnostics & Biomarkers Laboratory, Global Medical Education and Research Foundation, Hyderabad, India.
authors.forename: Lakshmi M
authors.initials: LM
authors.lastname: Chaturvedula
authors.affiliation: Molecular Diagnostics & Biomarkers Laboratory, Global Medical Education and Research Foundation, Hyderabad, India.
authors.forename: Venkataraman
authors.initials: V
authors.lastname: Sritharan
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Delhi, Hauz Khas, India. Electronic address: shalinig@chemical.iitd.ac.in.
authors.forename: Shalini
authors.initials: S
authors.lastname: Gupta
mesh_terms: D001681:Biological Assay / Q000379:methods*; D004731:Endotoxins / Q000097:blood* / Q000302:isolation & purification; D006046:Gold / Q000737:chemistry; D006801:Humans; D008567:Membranes, Artificial; D053768:Metal Nanoparticles / Q000737:chemistry*; D000067716:Point-of-Care Testing; D011112:Polymyxin B / Q000737:chemistry; D012680:Sensitivity and Specificity; D012772:Shock, Septic / Q000175:diagnosis*
chemical_list: D004731:Endotoxins; D008567:Membranes, Artificial; D006046:Gold; D011112:Polymyxin B
keywords: Endotoxin; Gold nanoparticle; Gram-negative bacteria; Lipopolysaccharide; Polymyxin B; Septicemia