Electronic single-molecule identification of carbohydrate isomers by recognition tunnelling

Carbohydrates are one of the four main building blocks of life, and are categorized asmonosaccharides (sugars), oligosaccharides and polysaccharides. Each sugar can exist in twoalternative anomers (in which a hydroxy group at C-1 takes different orientations) and eachpair of sugars can form different epimers (isomers around the stereocentres connecting thesugars). This leads to a vast combinatorial complexity, intractable to mass spectrometry andrequiring large amounts of sample for NMR characterization. Combining measurements ofcollision cross section with mass spectrometry (IM–MS) helps, but many isomers are stilldifficult to separate. Here, we show that recognition tunnelling (RT) can classify manyanomers and epimers via the current fluctuations they produce when captured in a tunneljunction functionalized with recognition molecules. Most importantly, RT is a nanoscaletechnique utilizing sub-picomole quantities of analyte. If integrated into a nanopore, RT wouldprovide a unique approach to sequencing linear polysaccharides.

Language

English

Source (journal)

Nature communications

Publication

2016

ISSN

2041-1723

DOI

10.1038/NCOMMS13868

Volume/pages

7 (2016) , p. 1-7