Lab-on-a-chip for ultrasensitive detection of carbofuran by enzymatic inhibition with replacement of enzyme using magnetic beads

Xavier Llopis, Martin Pumera, Salvador Alegret, Arben Merkoçi. Lab Chip, 9, p. 213 (2009)

In this paper an ultrasensitive method to determine toxicity due to pesticides in a glass lab-on-a-chip by means of enzymatic inhibition of acetylcholinesterase immobilised on magnetic beads is described. The reproducible insertion of a controlled amount of enzyme-coupled magnetic beads inside the chip channel and their immobilisation in a capture region with the aid of a magnetic field has been optimised. This procedure enables the easy renewal of the biosensing material after each determination in a highly reproducible manner. Several operational parameters such as the working potential for the selective detection ofthiocholine (TCh) on a platinum disc electrode, the TCh detection reproducibility and sensitivity, the electroosmotic flow driving voltage and the inhibition time were also evaluated or optimised. The detection ofcarbofuran (one of the most toxic carbamatepesticides) has been achieved down to the nanomolar level.

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