Direct Versus Competitive Biosensor Immunoassays for the Detection of (Dihydro)Streptomycin Residues in Milk

Abstract

A monoclonal antibody (MAb) against dihydrostreptomycin (4G8) was developed and its performance compared with a previously developed MAb against streptomycin (4E2) in biosensor immunoassays (BIAs) using a surface plasmon resonance (SPR)-based biosensor (BIACORE 3000). Direct BIAs for the detection of dihydrostreptomycin (DHS; 583 Da) and streptomycin (STREP; 581 Da) were developed by immobilising the MAbs on the sensor chip (CM5). These direct BIAs were compared with competitive inhibition BIAs, using a STREPprotein conjugate immobilized on the chip. The sensitivities of the direct and competitive BIAs for both drugs in buffer were comparable (10-20 ng ml -1 at 50% binding or inhibition). With milk, interferences, probably due to the nonspecific binding of proteins to the sensor chips, were observed in both BIAs. These interferences could be largely reduced using ultra filtration (UF) as sample pre-treatment. Another option was the use of a reference flow channel to correct for nonspecific binding. Using this option with five times diluted milk, MAb 4G8 was found to be suited for the direct BIA of both drugs with a limit of detection (LOD) of 20 ng ml -1 and both MAbs could be applied in the competitive BIA format with similar LODs.

Development and Single-Laboratory Validation of a Pseudofunctional Biosensor Immunoassay for the Detection of the Okadaic Acid Group of Toxins

“…[37][38][39][40][41][42][43][44][45][46] This labelfree, automated analysis technique combines the high affinity of biochemical interactions with low limits of detection producing rapid and reliable results. Minimal amounts of analyte are required to produce the chip surfaces, and these surfaces can be reused many times without loss of activity.…”

Development of a monoclonal antibody binding okadaic acid and dinophysistoxins-1, -2 in proportion to their toxicity equivalence factors

“…They produce rapid and reliable results with minimal sample preparation and use of analyte (Elliott et al, 1999;Gaudin et al, 2001;Gustavsson et al, 2002;Haasnoot et al, 2002;Mello and Kubota, 2002;Samsonova et al, 2002;Ferguson et al, 2002Ferguson et al, , 2005Gaudin et al, 2005;Traynor et al, 2006;Mauriz et al, 2006;Llamas et al, 2007;Campbell et al, 2007;Connolly et al, 2007, Campas et al, 2007. This technology allows for real time, automated analysis combining the high affinity of biochemical interactions with low limits of detection and is characterised by its simplicity of use.…”

The application of neoglycopeptides in the development of sensitive surface plasmon resonance-based biosensors

“…Nowadays, biosensors are widely applied for the detection, identification, and characterization of biological material, which is of great importance in industrial (Castillo et al, 2004), medical (Hsieh et al, 2004;Dillon et al, 2005;Jiang et al, 2005), food (Gustavsson et al, 2002;Haasnoot et al, 2002;Indyk and Filonzi, 2005;Muller-Renaud et al, 2005), and environmental (Castillo et al, 2004) analysis. Surface plasmon resonance-based biosensors are currently widely used to monitor these interactions (Chou et al, 2004;Oh et al, 2004;Choi et al, 2005).…”