Epitope imprinting of Sip D protein of Salmonella Typhi bacteria through multiple monomers approach

Typhoid fever is an endemic disease in India. An early stage detection of this disease will reduce the burden on healthcare industry and prevent many fatalities. Here a MIP sensor is fabricated to detect Salmonella typhi bacteria through its antigenic epitope sequence identified through immunoinformatic tools. Epitope imprinting through multiple monomers was utilized to deposit the sensing matrix on gold coated electrochemical quartz crystal microbalance (EQCM) electrode. Methacrylic acid, 2-methacryloyloxyethyl phosphorylcholine and benzyl methacrylate were used as monomers while ethylene glycol dimethacrylate as crosslinker and azobisisobutyronitrile was used as initiator. The analytical performance of MIP-EQCM sensor was studied by electrochemical as well as piezoelectric measurements. Selectivity of sensor was examined thorugh mismatched peptide sequences and certain plasma proteins also. The detection limit was found to be 0.27 ng mL⁻¹ by DPV and 0.87 ng mL⁻¹ by piezoelectric measurements. The sensor exhibited high selectivity towards imprinted epitope. Additionally, the sensor demonstrated the specific and selective detection in real sample of typhoid infected patients. Thus, the proposed MIP-EQCM sensor could be proposed as diagnostic tool for typhoid fever.