Methods and kits for removing particles from fluids

A method of separating solid particles from a fluid, the method comprising:

• a) obtaining a device comprising:
• 1) a microstructured substrate comprising a plurality of microstructures extending across a first surface of the microstructured substrate, wherein at least a portion of an exterior surface of the plurality of microstructures are configured to allow capillary action;
• 2) a cover disposed a selected distance apart from a top of the first surface of the microstructured substrate;
• 3) at least one sidewall that attaches the cover to the first surface of the microstructured substrate along a perimeter of the first surface of the microstructured substrate;
• 4) a first aperture defined by at least one of the microstructured substrate or the cover;
• and
• 5) a second aperture defined by at least one of the microstructured substrate or the cover;
• wherein the first surface of the microstructured substrate together with the at least one sidewall defines a first open volume that is a total of open space located between the plurality of microstructures from a bottom to a top of each microstructure, wherein the cover together with the top of the first surface of the microstructured substrate and the at least one sidewall defines a second open volume located adjacent to the first open volume, and taking a total of the combined first open volume and second open volume to be 100% open volume, the first open volume has a larger percent of the 100% open volume than a volume percent of particles that is present in the fluid;
• b) filling the device with a volume of the fluid through the first aperture via capillary action;
• c) waiting for a time sufficient for at least a portion of the particles to settle within the first open volume of the plurality of microstructures;
• and
• d) fluidically coupling the device with a collection article either at the first aperture or at the second aperture, thereby causing at least 10% of the initial volume of fluid, from which at least some of the particles have been retained within the first open volume of the plurality of microstructures, to flow out of the device and onto the collection article via capillary action.

A kit comprising a device and a collection article, wherein the device comprises:

• 1) a microstructured substrate comprising a plurality of microstructures extending across a first surface of the microstructured substrate, wherein the microstructures cover at least 90% of the first surface of the microstructured substrate and wherein at least a portion of an exterior surface of the plurality of microstructures are configured to allow capillary action;
• 2) a cover disposed a selected distance apart from a top of the first surface of the microstructured substrate;
• 3) at least one sidewall that attaches the cover to the first surface of the microstructured substrate along a perimeter of the first surface of the microstructured substrate;
• 4) a first aperture defined by at least one of the microstructured substrate or the cover;
• and
• 5) a second aperture defined by at least one of the microstructured substrate or the cover;
• wherein the first surface of the microstructured substrate together with the at least one sidewall defines a first open volume that is a total of open space located between the plurality of microstructures from a bottom to a top of each microstructure, wherein the cover together with the top of the first surface of the microstructured substrate and the at least one sidewall defines a second open volume located adjacent to the first open volume;
• and
• wherein the collection article has a surface that exhibits an advancing contact angle with water of less than 90 degrees.