Abstract: Substantially spherical polymer particles containing a colloidally, stably and uniformly dispersed magnetically responsive substance of about 5 nm to about 500 nm in diameter provide a superparamagnetic reagent carrier. Preferably, the polymer particles have a hydrated diameter of about 0.5 to 100 um, the polymer is a non-ionic cross-linked polyacrylamide gel and the magnetically responsive substance is iron oxide granules. The magnetically responsive substance may be present in an amount so that the polymer particles have a specific gravity of between 1.2 and 2.7. The reagent carrier is prepared by swelling polymer particles in a solution of iron salt so that substantially all of the iron salt solution is taken upon by the polymer particles and then converting the iron salt in situ to insoluble colloidally dispersed iron oxide granules.

Abstract: This invention provides a hydrophilic specific binding assay reagent which is prepared by a process comprising the steps of reacting a partner of a specific binding pair and at least one hydrophilic substance with haloalkyl moieties associated with the surface of a solid phase and recovering the reagent so prepared from any unreacted binding partner. Preferably, the alpha-haloalkyl is chloromethyl and the at least one hydrophilic substance comprises at least one protein, such as albumin, and at least one non-proteinaceous amine to which the solid phase is impermeable, such as tris (hydroxymethyl) aminomethane. The specific binding assay reagent of the invention can be combined with other reagents to provide an assay composition.

Abstract: An improved multi-tubular module is provided for use in ultrafiltration and reverse osmosis devices. Improved mechanical strength is achieved in the module by bonding the individual tubes to each other at spaced intervals along their total length whereby lateral and axial movement of individual tubes with respect to one another is eliminated, resulting in a coherent monolith of tubes. Additionally, improved resistance to thermal cycling is imparted to the module by connecting the tube sheet or header to the module shell in a manner which allows for slight movement of the tube sheet with respect to the module shell and yet provides a device which can be easily sanitized or sterilized when used for food or drug applications.