AUTOMATED MICROANALYSIS USING MAGNETIC BEADS WITH COMMERCIAL CAPILLARY ELECTROPHORETIC INSTRUMENTATION

The potential of a new microanalytical method using magnetic beads (MB s) and commercial capillary electrophoresis (CE) instrumentation for p erforming enzymatic and inhibition assays, as well as for analysis of biological molecules such as antigens, substrates, etc., has been expl ored. A small quantity of magnetic beads containing immobilized biomol ecules was injected into a neutral hydrophilic-coated fused-silica cap illary. The short plug (2-3 mm) of beads was held fixed by a magnet pl aced in the cartridge of the CE system, without the use of frits. The beads could be replaced after each run, eliminating the need to regene rate the solid support. Two protocols were used for analysis: sequenti al injection (SI) and SI followed by isotachophoretic (ITP) focusing. Alkaline phosphatase (AP) and HIV-protease were used to demonstrate th e SI procedure for enzymatic and inhibition assays. The second protoco l, SI/ITP, was employed to quantitate an antigen (mouse mAB) using ant ibodies (sheep IgG towards mouse AB) immobilized on the beads. The MB- CE method, requiring only femtomole (fmol) quantities of material, can potentially be employed in diagnostic and forensic assays, kinetic st udies and searching for inhibitors, ligands, receptors, etc. (C) 1997 Elsevier Science B.V.