A multilayer film of chitosan, 3.5 nm negatively charged CdSe quantum dots, and organophosphorus hydrolase was deposited onto quartz slide via the layer-by-layer deposition technique of polyelectrolytes. Concentration of paraoxon in solution was correlated to UV-Vis absorbance of the hydrolytic product p-nitrophenol and photoluminescence quenching of the quantum dots.

Constantine, C. A.; Gattás-Asfura, K. M.; Mello, S. V.; Crespo, G.; Rastogi, V.; Cheng, T.-C.; DeFrank, J. J.; Leblanc, R. M. Langmuir 2003, 19, 9863-9867

Constantine, C. A.; Gattás-Asfura, K. M.; Mello, S. V.; Crespo, G.; Rastogi, V.; Cheng, T.-C.; DeFrank, J. J.; Leblanc, R. M. J. Phys. Chem. B. 2003, 107, 13762-13764