Fabrication technique of pencil-type fibre probes and small apertures for photon scanning tunnelling microscopy

Abstract

In this work, 3-aminophenylboronic acid (APBA) functionalized dual-emission quantum dots (QDs) were prepared and utilized as the ratiometric fluorescence probe for the onsite naked eye determination of glucose. The unique ratiometric fluorescence probe, which combined ratiometric fluorescence technique with boric acid functional materials into one system, has been prepared by hybridizing red-emitting CdTe QDs (r-QDs) and green-emitting CdTe QDs (g-QDs). The fluorescence of the embedded r-QDs stays constant, whereas the g-QDs functionalized with APBA can selectively bind glucose by the chemistry of boronic acid and cis diol compounds, leading to the fluorescence of g-QDs quenched due to the surface quenching states induced mechanism and resulting in continuous fluorescence color changes (from green to red) of the ratiometric fluorescence probe system. Under optimum conditions, the proposed ratiometric probe was used for selective detection of glucose in a concentration range of 0.1–2.0 mmol/L with a detection limit of 4.5 μmol/L. Moreover, the developed ratiometric fluorescence probe was successfully applied to the detection of glucose in human serum samples. The present study provides an efficient and facile ratiometric fluorescence probe for rapid, convenient, sensitive and selective visual identification of glucose in blood glucose sensing without the need of complex equipment.