Design and development of a novel flexible molecularly imprinted electroanalytical sensor for the monitoring of diabetic foot ulcers

In this work, we report the development of a novel flexible electrochemical sensor based on molecular imprinting on over-oxidized poly-pyrrole, for monitoring DFUs (Diabetic Foot Ulcers). The latter are characterized by slow or non-healing chronic wounds which place a severe burden on day-to-day activities of affected patients. Given the drastic elevation of l-tyrosine concentrations in such circumstances, there lies a substantial demand for monitoring the quantity of this bio-marker via flexible sensing platforms for assessing the chronicity of foot ulcers in order to avoid co-morbidity, amputations and commencement of gross symptoms. The flexible molecularly imprinted sensor was fabricated on carbon screen-printed PET (Poly-ethylene Terephthalate) substrates, by electro-polymerization of pyrrole followed by templating of l-tyrosine in the polymer matrix. Microstructural characterizations of sensing surface were performed by FTIR (Fourier Transform Infrared Spectroscopy) and contact angle measurements; while the biomarker monitoring performance and its binding mechanism were evaluated by CV (Cyclic Voltammetry) studies. Further insights onto charge transfer kinetics at electrode-electrolyte interface, were obtained from EIS (Electrochemical Impedance Spectroscopy) and circuit simulation. The developed sensor demonstrated linear characteristics within a wide tyrosine concentration of 10 pM – 1 mM. The LoD (Limit of Detection) and sensitivity of the sensor were found to be 12.50 pM and 6.01 nA/pM/mm2 respectively with response time of less than a minute. The developed sensor was found to be highly selective towards tyrosine, owing to over-oxidized nature of templated poly-pyrrole, and was found to possess a shelf life of 3 months thereby fitting well within future connected health platform for DFU monitoring.