Tenfold enhancement of fluorescence quantum yield of water soluble silver nanoclusters for nano-molar level glucose sensing and precise determination of blood glucose level

[Display omitted] •A new water-soluble and highly luminescent silver nanocluster (AgNCs-a-APBA) have been designed and synthesized.•The high selectivity and ultrasensitivity of the material towards glucose (up to nano-molar range) have been explored.•A new method has been designed and developed for the precise determination of human blood glucose level.•The mechanism of fluorescence enhancement in presence of 3- aminophenyl bronic acid and its quenching in presence of trace amount glucose has been searched. Specially designed water soluble fluorescent silver nanoclusters anchored with 3-aminophenyl boronic acid (AgNCs-a-APBA) have been synthesized sonochemically in environmentally benign water medium. The new material (AgNCs-a-APBA) shows tenfold enhancement of fluorescence intensity compared to AgNCs. Fluorescence quenching experiments reveals its precise glucose sensing property up to nano-molar level. The method utilized to check glucose level in human blood sample and the results are compared with conventional data obtained from Glucometer and Colorimetric/Fluorometric Assay kit. The role of APBA in enhancing fluorescence property has been explained. The hydrogen bonding-driven aggregation of APBA with AgNCs and the glucose-triggered disaggregation of the nanoclusters are investigated in details. The synthesized materials are characterized with the help of conventional experimental techniques such as UV–vis, TEM, HR-MS, FTIR, SAED, XRD, DLS and fluorescence measurements.