Micro-fluidic system using micro-apertures for high throughput detection of cells

A method for detecting at least two different types of target entities in a fluid sample, the method comprising:

• mixing the fluid sample with a plurality of first magnetic beads and a plurality of second magnetic beads to form a fluid sample mixture, wherein the first magnetic beads bind to first target entities and the second magnetic beads bind to second target entities, and wherein each first target entity has a smallest effective dimension greater than a largest effective dimension of each second target entity and greater than a largest effective dimension of each of said first and second magnetic beads;
• flowing the fluid sample mixture through a detector component, wherein the detector component comprises
• a body defining a reservoir;
• a plate arranged within the reservoir to separate the reservoir into a first chamber and a second chamber, wherein the plate defines a plurality of openings therethrough with each opening having an effective dimension that is larger than the largest effective dimension of each of the first and second magnetic beads and of the second target entities and smaller than the smallest effective dimension of the first target entities;
• and
• applying a first magnetic force sufficient (i) to draw at least some of the first and second magnetic beads not bound to one of the first or second target entities through the openings in the plate from the first chamber into the second chamber, (ii) to draw at least some of the second target entities bound to the second magnetic beads through the openings in the plate from the first chamber into the second chamber, and (iii) to attract and hold at least some of the first target entities bound to the first magnetic beads against a surface of the plate within the first chamber of the reservoir, such that the first target entities are not dislodged from the surface of the plate by the fluid sample mixture flowing through the first chamber.