A method for arranging microspheres in a non-aqueous liquid phase

A method for arranging microspheres in a non-aqueous, water-immiscible liquid phase in an incubation chamber and for excluding such microspheres from contact with or exposure to a gas phase, said method comprising the steps:

• a) providing, in any order, a suspension comprising magnetic microspheres suspended in a non-aqueous, water-immiscible liquid phase, and an incubation chamber;
• said incubation chamber having a closed bottom, an open top, at least one wall, and a defined volume;
• said open top being spaced apart from said closed bottom by a defined distance;
• said chamber being dimensioned to accommodate a defined volume of said suspension therein;
• said magnetic microspheres having a first defined density;
• said non-aqueous, water-immiscible liquid phase having a second defined density, and wherein said first defined density <said second defined density;
• b) filling said incubation chamber with said suspension by placing said suspension into said incubation chamber, such that in said incubation chamber, at the open top or at a first position along said defined distance between said open top and said closed bottom, there is formed a first interface between said non-aqueous, water-immiscible liquid phase and a gas phase, such gas phase surrounding said incubation chamber;
• c) removing said magnetic microspheres from said first interface or keeping them removed therefrom by attracting said magnetic microspheres to the closed bottom of said incubation chamber or to said at least one wall, wherein said attracting is achieved by exerting a magnetic force across said closed bottom or across said at least one wall of said incubation chamber;
• d) whilst keeping said magnetic microspheres attracted to the closed bottom or to said at least one wall of said incubation chamber by continuing to exert a magnetic force across said closed bottom or said at least one wall, placing a solid surface at said open top of said incubation chamber or at a position along said defined distance between said open top and said closed bottom of said incubation chamber;
• wherein such placing occurs such that said solid surface is in contact with said liquid phase and such that at said open top or at said position there is formed a second interface between said non-aqueous, water-immiscible liquid phase and said solid surface, wherein such second interface replaces or eliminates said first interface and thereby excludes said gas phase from being in contact with said liquid phase;
• and
• e) allowing the magnetic microspheres to assemble at the second interface by ceasing to exert a magnetic force across said bottom or across said at least one wall of the incubation chamber, thereby releasing said microspheres from said bottom or from said at least one wall.