Boronate affinity-mediated multi-mode visual sensing of cis-diol compounds in both biological and food samples

cis -Diol compounds are of great biological and clinical values, but their detection is usually instrument-inseparable. Herein, a flexible sensing strategy was proposed at the first time for multi-mode visualization of cis -diol compounds based on boronate affinity (BA)-mediated colorimetry and fluorometry. Boronic acid-decorated sensors with color-/fluorescence-derived binary responsivity were designed using cis -diol fluorescent dyes or dyes-fluorophore counterparts as response units, inducing competitive BA when cis -diol analytes were existed. Consequently, colors and fluorescence of sensors changed simultaneously, and both signals were linearly varied versus the dosages of cis -diol analytes in certain ranges. As proofs of concept, dual-mode visual sensing of glucose in normal/hyperglycemic human serum and sucrose in canned white fungus and edible mushroom plant beverage was achieved with sensing time as short as 1   min and limit of detection as low as 0.18   mg/mL. Furtherly, color information of colorimetric/fluorometric cards and tested sensors was picked by a smartphone APP for digital image analysis, by which the validity of dual-mode visual sensing assays was reinforced by avoiding possible errors from subjective judgement on colors and fluorescence. Besides, the credibility of visual sensing was cross-validated by fluorescent quantification and classical tools such as portable blood glucose meter and phenol-sulfuric acid method-based halochromic reaction.