Epitope imprinting of Mycobacterium leprae bacteria via molecularly imprinted nanoparticles using multiple monomers approach.

Mycobacterium leprae causes endemic disease leprosy which becomes chronic if not treated timely. To expedite this 'timely diagnosis', and that also at an early stage, here an attempt is made to fabricate an epitope-imprinted sensor. A molecularly imprinted polymer nanoparticles modified electrochemical quartz crystal microbalance sensor was developed for sensing of Mycobacterium leprae bacteria through its epitope sequence. Multiple monomers, 3-sulphopropyl methacrylate potassium salt, benzyl methacrylate and 4-aminothiophenol were utilized to imprint this bacterial epitope. Imprinted nanoparticles were electropolymerized on gold coated quartz electrode. The sensor was able to show specific binding towards the blood samples of infected patients, even in the presence of 'matrix' and other plasma proteins such as albumin and globulin. Even other peptide sequences, similar to epitope sequences only with two amino acid mismatches were also unable to show any binding. Sensor withstood analytical tests viz. selectivity, specificity, matrix effect, detection limit (0.161 nM), quantification limit (and 0.536 nM), reproducibility (RSD 2.01%). Hence a diagnostic tool for bacterium causing leprosy is successfully fabricated in a facile manner which will broaden the clinical access and efficient population screening can be made feasible.

Electrochemical and piezoelectric monitoring of taurine via electropolymerized molecularly imprinted films.

A molecularly imprinted electrochemical quartz crystal microbalance (EQCM) sensor is fabricated here for taurine, a ß-amino acid significant for functioning of almost all vital organs. The polymeric film of l-methionine was electrochemically deposited on gold-coated EQCM electrode. Experimental parameters were optimized for controlling the performance of molecularly imprinted polymer (MIP)-modified sensor such as ratio of monomer and template, number of electropolymerization cycles, mass deposited in each cycle, and pH. Thus, fabricated MIP-EQCM sensor was successfully applied for estimation of taurine in solutions with varying matrices, such as aqueous, human blood plasma, milk from cow, buffalo, and milk powder. Under optimized parameters, response of MIP sensor to taurine was linearly proportional to its concentration with limit of detection as 0.12µM. Hence, a highly sensitive and selective piezoelectric sensor for taurine has been reported here via imprinting approach.