A fluorescence-electrochemistry dual-mode imprinted sensing platform constructed by boric acid-functionalized MOF@COF core-shell composite for sensitive detection of glycoprotein

A novel imprinted material for glycoprotein detection was prepared based on metal-organic framework (MOF)/covalent-organic framework (COF) hybrid composite (MOF@COF-B(OH)2) with fluorescent properties and boric component that facilitated glycoprotein imprinting. The MOF@COF-B(OH)2 exhibited improved fluorescence emission from MOF due to efficient excited-state intramolecular proton transfer (ESIPT). Transferrin (TrF), an important transporting glycoprotein, was selected as the target. MOF@COF-B(OH)2 effectively captured TrF through boronated affinity. The imprinted material (MOF@COF-B(OH)2@MIP) showed obvious fluorescence quenching after incubation with TrF at 430 nm via the photo-induced electron transfer (PET). A good linear relationship was demonstrated in the range of 0.1–40 µM with an associated limit of detection (LOD) of 57.6 nM under optimal conditions. An electrochemical platform for TrF detection was constructed by combining MOF@COF-B(OH)2@MIP with a disposable screen-printed carbon electrode (SPCE). The differential pulse voltammetry signal generated by MOF@COF-B(OH)2@MIP/SPCE served as a secondary signal to monitor TrF. The MOF@COF-B(OH)2@MIP/SPCE exhibited satisfactory linearity with a LOD of 2.7 nM. Moreover, the imprinted sensor showed good recovery rates for detection in actual samples using fluorescencent and electrochemical modes. This study offered a promising strategy for the application of boric acid-functionalized MOF@COF in glycoprotein sensing.