Poly(Ethyleneimine)‐Immobilized‐Cloth Enzyme Immunoassay for the Detection of Salmonella Lipopolysaccharide

Abstract

Poly(ethyleneimine) (PEI) was immobilized on non‐woven polyester cloth and examined for application on a simple, rapid and economical “cloth enzyme immunoassay (CEIA)” which was developed originally as polymyxin‐CEIA for the detection of Salmonella lipopolysaccharide (LPS). PEI‐cloth regardless of the PEI molecular weight, but with the amine group contents of 0.1 ∼ 0.35 meq/g immobilized either in a physisorption‐like or chemisorption‐like manner, adsorbed LPS rapidly, preferentially and effectively. The captured LPS was then able to be detected qualitatively and quantitatively as an antigen by enzyme immunoassay. PEI‐CEIA had a detection limit for Salmonella LPS of 10 ng/ml, which was equivalent to 1.6 × 105 cell/ml and was ten times more sensitive than polymyxin‐CEIA. It was possible to detect Salmonella LPS in the presence of a 100‐fold excess of E. coli LPS. PEI‐CEIA was found to be more sensitive and much easier to carry out than polymyxin‐CEIA but had the same advantages as polymyxin‐CEIA.