The nCounter® Analysis System from NanoString Technologies uses a digital technology based on molecular barcodes and single molecule imaging to achieve direct multiplexed measurements of gene expression. The system includes a fully automated sample-prep station, a digital analyzer, CodeSet barcodes, and the necessary reagents and consumables.
nCounter technology creates a series of unique tags, which differ by the combination and position of four colors. Using four colors and eight possible tag positions, for example, 48 or 65,536 unique tags can be created. Each tag is chemically linked to a target-specific probe (a sequence-specific oligonucleotide) to produce a reporter probe. The reporter probes are then pooled to form a CodeSet that is mixed with a sample, such as a total RNA extract, and allowed to hybridize in a single reaction.
Removal of unhybridized probes and subsequent imaging of the bound individual reporter probes yields a count of the number of copies of each code, and thus of each gene, that is present in the sample. In comparative studies, the company showed the nCounter system to be more sensitive than microarray-based methods and similar in sensitivity to real-time PCR.
Earlier this year the FDA put out a call for volunteers to participate in the Sequencing Quality Control (SEQC) project, intended “to objectively assess the technical performance of different next-generation sequencing technologies in DNA and RNA analyses and to evaluate the advantages and limitations of various bioinformatics solutions in handling and analyzing the massive new data sets.”
The FDA views SEQC as a natural extension of its MicroArray Quality Control project, which evaluated and compared various microarray-based methods and technologies for gene-expression profiling.