Fig. 2: Sensing of target cis-diols.
a Target cis-diols investigated in this manuscript. Four kinds of cis-diols, including 1,2-diphenols (purple), alditols (green), α-hydroxy acids (pink) and saccharides (orange), all contain cis-dihydroxyl groups, as red-marked (top). For each kind of cis-diols, a few representative analytes were selected as target cis-diols (bottom). b The phenylboronic acid (PBA) modified nanopore sensor (Methods). Cis-diols reversibly react with PBA (Supplementary Fig. 1), generating characteristic events when sensed by MspA-PBA. c–l The chemical structures and corresponding nanopore events of target cis-diols, catechin (CAT) (c), neochlorogenic acid (3-CQA) (d), D-sorbitol (D-SOR) (e), xylitol (XYL) (f), L-malic acid (L-MA) (g), L-tartaric acid (L-TA) (h), citric acid (CA) (i), (2R,3)-isocitric acid (ICIT) (j), D-glucose (D-GLC) (k) and D-fructose (D-FRU) (l). The abbreviations of these cis-diols were marked in the corresponding bracket. The open pore currents were marked by I0. All nanopore measurements were performed in a buffer of 1.5 M KCl, 100 mM MOPS, pH 7.0 and a continually applied bias of +160 mV. Each type of cis-diol was added as a sole analyte to both cis and trans chambers (Methods). In this paper, alditols, 1,2-diphenols and α-hydroxy acids all showed only one type of event while saccharides showed several types of events.
