Design and development of an electroanalytical sensor based on molecularly imprinted polyaniline for detection of thyroxine

Hypothyroidism and hyperthyroidism are one of the most frequently observed endocrine disorders in the world. Failure to undergo timely diagnosis and treatment often results in life-threatening events such as arrythmia, hypertension and cardiac arrest. Considering the various limitations of conventional diagnostic techniques, early, accurate and efficient diagnosis of these disorders is pivotal for their timely management. In the present work, a Molecularly Imprinted Polymer (MIP) based sensor is developed for the detection of thyroxine (T 4 ) – the key biomarker. This has been achieved by templating T 4 into polyaniline matrix supported on Indium Tin Oxide (ITO) coated glass electrodes. The chemical synthesis of polyaniline was done through oxidative polymerization and optimized using Response Surface Methodology (RSM). The optimum conditions for ultrasonication based extraction of T 4 from polyaniline matrix was 15min at 30°C with 75mM NaOH. The developed MIP based sensor was characterized using chromatographic, spectroscopic and electrochemical techniques. The sensor calibration was obtained within T 4 concentration range of 5pg/mL – 50pg/mL, with a calculated Limit of Detection (LoD) of7.96pM (6.16pg/mL). The developed MIP-based electroanalytical sensor was found to exhibit high degree of selectivity against various interferants, and thereby possessing huge prospects towards futuristic point-of-care applications.