Regeneration of immunosorbent surfaces used in clinical, industrial and environmental biosensors. Role of covalent and non-covalent interactions.

The durability and regeneration of antibodies immobilized to commercial immunosorbents were investigated by monitoring Ag-Ab dissociation. Solutions consisting of 0.01 M hydrochloric acid (HCl), 10% propionic acid, 50% ethylene glycol and 10% SDS in 6 M urea were used in the evaluation of antigen dissociation from antibody covalently immobilized to glass and polystyrene beads, microtiter plates and Immobilon filters. RAH-IgG, used as a model antibody, bound strongly to all covalent surfaces. However, on adsorption to Nunc-1 microtiter plates, 25-60% of RAH-IgG was removed by all dissociating solutions. Covalent binding to Sanger beads was weakest relative to other covalent surfaces, exhibiting 30% and 65% detachment with ethylene glycol and SDS in urea, respectively. Although all four solutions dissociated antigen from surface-bound antibody, HCl and propionic acid were more effective on most surfaces. The antibody remained functional following antigen dissociation and reassociated to nearly 100% on all surfaces except Sanger beads and Nunc-1 microtiter plates. This study was initiated to evaluate regeneration and reuse of microelisa plates and emerging biosensors as a means of reducing routine laboratory analysis costs. Data are presented to demonstrate the reusability of microtiter plates in ELISAs following antigen dissociation from covalently bound antibody.