Immobilisation of antibodies and antigens on macro solid phases--a comparison between adsorptive and covalent binding. A critical study of macro solid phases for use in immunoassay systems. Part I.

This article describes a comparison between adsorption and covalent binding of protein-conjugates (bovine serum albumin-diazoluminol), antibodies (sheep anti-human thyrotropin) and haptens ([125]thyroxine) to polystyrene, nylon and glass balls. Different combinations of adsorption and covalent binding were used; these varying with the solid phase in question. Polystyrene balls were preactivated by adsorption of a copolymer of phenylalanine and lysine (poly phe-lys) from aqueous solution. The treated balls were then in most cases chemically activated with pentane-1,5-dial before coupling the substance under test. Polystyrene balls were directly chemically activated by nitration followed by reduction and diazotisation. Nylon balls were either used as received or partially hydrolysed with either hydrochloride acid or sodium hydroxide before further use. Chemical activation was carried out using either carbodiimides or pentane-1,5-dial, the latter proving to be unsuitable because of cross-linking between amino groups on the ball surface. Glass balls were coated with organofunctional aminosilanes followed by chemical activation with pentane-1,5-dial. The best results were obtained using nylon balls activated with carbodiimides and with polystyrene balls coated with poly phe-lys and chemically activated with pentane-1,5-dial. Glass balls proved to be unsuitable as the coating precision was poor under laboratory conditions.