Electronic single-molecule identification of carbohydrate isomers by recognition tunnelling

Jong One Im, Sovan Biswas, Hao Liu, Yanan Zhao, Suman Sen, Sudipta Biswas, Brian Ashcroft, Chad Borges, Xu Wang, Stuart Lindsay, Peiming Zhang

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


Carbohydrates are one of the four main building blocks of life, and are categorized as monosaccharides (sugars), oligosaccharides and polysaccharides. Each sugar can exist in two alternative anomers (in which a hydroxy group at C-1 takes different orientations) and each pair of sugars can form different epimers (isomers around the stereocentres connecting the sugars). This leads to a vast combinatorial complexity, intractable to mass spectrometry and requiring large amounts of sample for NMR characterization. Combining measurements of collision cross section with mass spectrometry (IM-MS) helps, but many isomers are still difficult to separate. Here, we show that recognition tunnelling (RT) can classify many anomers and epimers via the current fluctuations they produce when captured in a tunnel junction functionalized with recognition molecules. Most importantly, RT is a nanoscale technique utilizing sub-picomole quantities of analyte. If integrated into a nanopore, RT would provide a unique approach to sequencing linear polysaccharides.

Original languageEnglish (US)
Article number13868
JournalNature communications
StatePublished - Dec 21 2016

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • General
  • Physics and Astronomy(all)


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