Neoglycoconjugates, i.e. de novo synthesized conjugates of glycosides and carrier molecules such as proteins or polylipids, were used as affinity ligands in a surface plasmon resonance (SPR) biosensor assay. The affinity of the glycoconjugates, normally in the lower affinity range, was influenced by increasing the number of glycosides bound per carrier protein, the coupling chemistry, and the assay temperature. As a model system, albumin-conjugated A- and B-active blood group oligosaccharides with suitable linker molecules were chosen. Specific monoclonal antibodies were used as analytes to verify the interactive performance. Affinity kinetics of the systems were evaluated from the SPR biosensor data. The results demonstrate that neoglycoconjugates are a good alternative in presenting affinity ligands of small, specific molecules in SPR-based assays with retained specificity and bioavailability. ⌐ 2001 Elsevier Science B.V. All rights reserved.

A multitude of weak biological interactions, either working alone or in concert, occur frequently throughout biological systems. We have used this natural feature of readily reversible interactions as the basis for continuous immunosensing. In a model system, a set of weak monoclonal antibodies directed towards a carbohydrate epitope was studied with the aid of surface plasmon resonance. Because the system requires no regeneration, it can be used as a truly on-line immunosensing device. This principle should have wide application in all areas where there is a need for the continuous evaluation of a molecule.

An immunosensing system based on surface plasmon resonance (SPR) was used for on-line detection and characterization of carbohydrate molecules separated by high-performance liquid chromatography. These analytes, with or without serum, were continuously separated and analyzed in the combined liquid chromatography-surface plasmon resonance (LC-SPR) system. By using weak and readily reversible monoclonal antibodies, the SPR system allowed specific on-line monitoring of the substances. To increase the specificity of the immunosensor, nonrelevant antibodies were used as reference in a serial flow cell. The sensitivity of the LC-SPR system was dependent on molecular weight of the carbohydrate, affinity of binding, and design of the sensor. (C) 2000 Academic Press.