公开(公告)号：US20250069787A1

公开(公告)日：2025-02-27

申请号：US18713584

申请日：2022-11-23

Applicant: Roche Diagnostics Operations, Inc.

Inventor： Martin Eduardo Silvestre ,  Sabine Eisold ,  Dieter Heindl ,  Kristina Peters

IPC: H01F1/33 ,  H01F1/00 ,  H01F1/34

Abstract: In a first aspect, the invention relates to a method for preparing a magnetic bead comprising at least one magnetic particle (M) and a silica coating, wherein the silica coating comprises at least two silica layers, the method comprising steps (a) to (d), wherein at least one of steps (b), (c) and (d) is/are done under sonication, wherein sonication is done with an amplitude (peak-to-peak) in the range of from 50 to 250 μm. A second aspect of the invention is related to a magnetic bead comprising (i) at least one magnetic particle (M) and (ii) a silica coating, wherein the silica coating comprises at least two silica layers; wherein the magnetic bead is stable against 7.5 M hydrochlorid acid and has a metal (cation) leaching rate in 7.5 M hydrochloric acid in the range of from 0.1 to 10%, wherein the metal (cation) leaching is determined according to a complex formation of Fe2+ with bathophenanthroline according to Reference Example 8.2. In a third aspect, the invention relates to a functionalized magnetic bead comprising at least one, magnetic bead according to the second aspect, wherein an outer silica layer is functionalized with at least one group selected from the group consisting of amino group, azide group, alkyne group, carboxyl group, thiol group, epoxy group, aryl group and alkyl group. A fourth aspect of the invention is directed to a process for functionalizing a magnetic bead according to the second aspect comprising at least one magnetic particle (M) and a silica coating, wherein the silica coating comprises at least two silica layers. A fifth aspect of the invention is related to a method for preparing magnetic Fe3O4 supra particles and a sixth aspect relates to the use of a magnetic bead according to the second aspect or of a functionalized according to the fourth aspect for immobilization of acid stable biocatalysts or for solid-phase organic synthesis using acid-stable linker.