Tak Chuen Wong

US Patent:

52061590, Apr 27, 1993

Filed:

Aug 25, 1992

Appl. No.:

7/934287

Inventors:

Beri Cohen - White Plains NY
Tak K. Wong - Hamden CT
Bartholomew Hargitay - White Plains NY

Assignee:

Miles Inc., as Legal Successor by Merger with Technicon Instruments Corp. - Tarrytown NY

International Classification:

C12N 1108
C12Q 100
G01N 3353
G01N 33545

US Classification:

435180

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. Converting of the iron salt may be carried out by reacting the iron salts with a base to form iron hydroxide and subsequently converting the hydroxide by heating to iron oxide. The polymer particles are particularly useful as a reagent carrier in automated immunoassays.