Electronic tongue for simultaneous detection of endotoxins and other contaminants of microbiological origin

JORGE YANEZ HERAS; DIEGO PALLAROLA; FERNANDO BATTAGLINI

BIOSENSORS & BIOELECTRONICS

ELSEVIER ADVANCED TECHNOLOGY

Lugar: Amsterdam; Año: 2010 vol. 25 p. 2470 - 2476

0956-5663

Endotoxins, also referred to as pyrogens, are lipopolysaccharides (LPS) present in the outer membraneof Gram-negative bacteria, and represent one of the most dangerous microbiological contaminants inwater for hemodialysis and intravenous infusion. A method is presented for the simultaneous detection ofendotoxins and other bacterial lysis contaminating species in purified water for parenteral formulations.The technique used is electrochemical impedance spectroscopy, with data interpretation using principalcomponent analysis (PCA), cluster analysis (CA), and multivariate discriminant analysis (MDA). Two typesof electrode surfaces were modified with LPS recognition agents: (i) a 37 amino acids fragment of a 18 kDacationic antimicrobial protein (CAP18F) that has LPS binding activity; (ii) the highly selective endotoxinneutralizing protein (ENP). Statistical multivariate analysis of the impedance spectral data allowed thedetection of endotoxin at, and below, the threshold pharmaceutical regulatory level. Discrimination ofLPS from samples containing proteins, nucleic acids, phospholipids or their mixtures was achieved. Theseresults open a new route to a practical instrumental method capable of detecting and discriminating LPSfrom other potential pro-inflammatory species of microbiological origin, such as nucleic acids.