Aptamer functionalized ZnO thin-film transistor based multiplexed detection of Lead and E. coli in water

Background: Contamination of lead (Pb 2+) disturbs biological functions and causes neurotoxicity even at low levels. Pathogens such as Escherichia coli, P. aeruginosa and S. aureus found in packaged drinking water causes infections. Therefore, we demonstrate the multiplexed detection of Pb 2+ and E. coli in water using ZnO thin-film transistor (TFT) arrays. Results: : Low voltage ZnO TFTs fabricated by physical vapour deposition were functionalized with APTES-glutaraldehyde molecules. TFTs with such functionalized ZnO surfaces showed good sensitivity and high specificity to the targets. The TFTs showed a detection limit of 27 nM and 10 5 cfu/ml for Pb 2+ and E. coli, respectively with the TFT flat-band voltage (V fb), and hence the TFT transconductance, being dependent on the target concentration. The direct integration of the sensing with the TFT and associated integrated circuits promises high density sensor arrays. Conclusion: The present work highlights the importance of aptamers in the multiplexed detection of different targets using low cost ZnO TFT array.