Methods and systems are provided for concentrating particles (e.g., bacteria, viruses, cells, and nucleic acids) suspended in a liquid. Electric-field-induced forces urge the particles towards a first electrode immersed in the liquid. When the particles are in close proximity to (e.g., in contact with) the first electrode, the electrode is withdrawn from the liquid and capillary forces formed between the withdrawing electrode and the surface of the liquid immobilize the particles on the electrode. Upon withdrawal of the electrode from the liquid, the portion of the electrode previously immersed in the liquid has particles immobilized on its surface.