An apparatus for conducting a highly sensitive assay is provided wherein the level of a specific material is detected using a reaction which produces a detectable substance such as a colored dye or a fluorescent material in proportion to the concentration of the material being detected and which is carried...http://www.google.com.au/patents/US5196302?utm_source=gb-gplus-sharePatent US5196302 - Enzymatic assays using superabsorbent materials
