NanoString's core technology allows us to create many different unique "tags" and individually attach them to different target specific molecules. These unique tags provide a mechanism for identifying many different individual molecules in a complex biological sample. Unique tags are created through a combination of different colors and different positions. Additional codes may be created by simply increasing the number of colors or positions on the tag. This high level of multiplexing enables many biological applications that rely on simultaneous measurement of molecules of interest.

Unique Tags

The combinatorial power of this approach makes it possible with a small number of positions and colors to create tens of thousands of differently coded tags. For example, with 4 colors and 8 positions, 4⁸ (or 65,536) unique tags may be created.

Reporter Probes

Each unique tag, or code, is chemically linked to a target specific probe to create a Reporter Probe. Target specific probes selectively bind only to their complement. In combination with a unique code, Reporter Probes may be pooled together into a single reaction to create a highly multiplexed CodeSet. In the case of mRNA, we attach a sequence specific oligonucleotide to the code and hybridize the Reporter Probe to the gene of interest.

Hybridization in Solution

A solution of test sample, for example an extract of total RNA, is mixed with NanoString Reporter Probes allowing the hybridization reaction to occur in solution. Favorable hybridization kinetics exist in solution when compared to the same reaction where the DNA probe is attached to a solid substrate.

No Enzymology

There is no enzymology required for sample preparation.  To analyze gene expression levels, extracts of total RNA can be measured directly without the need for reverse transcription (RT) or amplification. Not only are these timely and costly steps eliminated, but the inherent bias of amplification is removed from the measurement.

Digital Data

After hybridization we remove excess reporter probes and image the individual Reporters that hybridized to a target molecule. Since we are imaging individual molecules, we are able to count the number of times each code is found present in the sample.