Abstract: Method of enriching specific cells from cellular samples are disclosed, comprising contacting in solution a cellular sample with affinity-tagged ligands (ATLs) each comprising a first ligand linked to an affinity tag, wherein the ligand selectively binds a cellular marker of the rare cells and the affinity tag can be selectively captured by a capture moiety, wherein the affinity tags do not comprise a magnetic particle; and flowing the sample through a microfluidic device comprising the capture moiety to selectively retain ATL-bound cells. Methods for enriching circulating tumor cells, and devices for enriching specific cells from cellular samples are also disclosed.