Sensitive impedimetric detection of E. coli with metal-organic framework (MIL-53)/polymer (PEDOT) composite modified screen-printed electrodes

Abstract Present work details the development of an electrochemical biosensing system for E. coli. A composite of a metal-organic framework (MOF), i.e., MIL-53 (Fe) (MIL = Materials of Institut Lavoisier) with poly(3,4-ethylenedioxythiophene) polystyrene sulphonate (PEDOT:PSS) has been prepared and used to modify the carbon-screen printed electrodes (cSPE). Due to the addition of PEDOT:PSS, the composite has exhibited electrochemical conductivity along with several other known beneficial features of MOF. The composite modified cSPE has been functionalized with anti-E. coli antibodies to guarantee the specificity of the detection. The present electrochemical sensor, based on the measurement of electrochemical impedance spectroscopic and different pulse voltammetry signals, has allowed the detection of E. coli over a wide concentration range of 2.1×102 to 2.1×108 cfu/mL, with the best detection limit of 4 cfu/mL. The sensor could also tolerate the co-presence of other possibly interfering species, such as S. aureus and S. arlettae. The results obtained from the present system have been validated against standard techniques.