An electrochemical paper-based microfluidic device modified with molecularly imprinted polymer-coated ZnFe2O4@MIL-101(Cr)@SiO2 for ultrasensitive and highly selective detection of streptomycin

In the current study, an analytical device based on electrochemical paper modified with molecularly imprinted polymer (MIP) with good structural stability and high sensitivity was designed to determinate streptomycin. The molecularly imprinted polymer was fabricated using a metal-organic framework (MOF), ZnFe2O4@MIL-101 (Cr), as a sensing platform. ZnFe2O4@MIL-101(Cr) nanocomposites were synthesized using one-step hydro- thermal method and encapsulated with silica to construct a molecularly imprinted sensor. In the MIP-sensor, ZnFe2O4@MIL-101(Cr) was used as carrier, silica precursor molecules and streptomycin as monomer and template molecule, respectively. The morphology of MIP sensor (ZnFe2O4@MIL-101(Cr)@SiO2) was evaluated using FE-SEM and FT-IR. To assess the detection performance of the imprinted molecular sensor, electrochemical method was utilized. The re-adsorption of STR into the carved holes decreased the electrochemical intensity. Due to STR molecules are not reactive and blocking the holes, they decrease the electrochemical intensity of [Fe (CN)6]3-/4- . The MIP sensor showed a remarkable linear response to STR from 1 pM to 1 mM with a detection limit of 0.97 x 10-12 M. The size of the streptomycin sulfate molecule is 992 degrees A and the size of the holes created on the particles is less than 100 nm. Therefore, the holes created on the particles are thought to be related to the successful imprinting of STR template molecules and the formation of imprinted holes in ZnFe2O4/MIL-101(Cr) @SiO2-MIP.