Abstract: A testing system and test cartridge for analyzing a sample of water from a water source for specific analyte levels. The test cartridge including a membrane filter that captures a target analyte while allowing a labelled conjugate to permeate through the membrane. The conjugate includes an analyte-specific labelled binding reagent to bind with the target analyte for optical detection. The direct membrane interrogation (i.e., on-filter detection), determines analyte levels without elution of the analyte from a filter thereby improving analyte recovering and assay sensitivity.

Abstract: The invention encompasses novel sensor designs that can operate in complex samples like whole blood. The use of protective filtering membranes prevents fouling and erroneous signal drift in sensors such as aptamer based electrochemical sensors. In one aspect, the invention encompasses implantable sensors that can be deployed to the circulatory system of an animal where they can accurately and continuously measure the concentration of a target species, such as a drug, with very short resolution times, for extended periods without signal drift. These sensor designs and associated methods provide a means of accurately dosing animals based on real-time monitoring of drugs and other chemical markers and biomarkers.