Abstract

An increasingly important set of tools for life scientists are reagents for multiplexing, the capability to simultaneously detect multiple biological species in the same sample volume at the same time. Optical detection tags are molecules (e.g. fluorescent molecules), or larger entities (e.g. nanoparticles) that are attached to a biological species, and exploit light to quantify the biological species’ presence and/or location. Optical detection tags, the newest of which are 60 years old, have been a central component of such seminal biological tools as the immunoassay, the microarray, and DNA sequencing, and they are omnipresent in the research lab and the clinical lab. For example, current tests for blood groups (ABO/Rh) involve separate tests for each blood type, and additional (separate) tests for pathogens such as syphilis, HIV, West Nile Virus, SARS, etc. Ideally, one would like to carry out all these measurements at once, in the same vial; however, this would take 10+ different tags that can be seen in a whole blood sample. Unfortunately, with existing optical tags, there are neither enough different types, nor are the existing types of the right “color” for whole blood assays. In short, life science bioassays, including diagnostic tests, increasingly require information-rich measurements, but rely on ancient, information-poor technologies.

© 2005 Optical Society of America