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Vectorially imprinted hybrid nanofilm for acetylcholinesterase recognition

: Jetzschmann, Katharina J.; JJágerszki, Gyula; Dechtrirat, Decha; Yarman, Aysu; Gajovic-Eichelmann, Nenad; Gilsing, Hans-Detlev; Schulz, Burkhard; Gyurcsányi, Róbert E.; Scheller, Frieder W.


Advanced Functional Materials 25 (2015), Nr.32, S.5178-5183
ISSN: 1616-301X
ISSN: 1616-3028
Bundesministerium für Bildung und Forschung BMBF
Fraunhofer IZI ()

Effective recognition of enzymatically active tetrameric acetylcholinesterase (AChE) is accomplished by a hybrid nanofilm composed of a propidium-terminated self-assembled monolayer (Prop-SAM) which binds AChE via its peripheral anionic site (PAS) and an ultrathin electrosynthesized molecularly imprinted polymer (MIP) cover layer of a novel carboxylate-modified derivative of 3,4-propylenedioxythiophene. The rebinding of the AChE to the MIP/Prop-SAM nanofilm covered electrode is detected by measuring in situ the enzymatic activity. The oxidative current of the released thiocholine is dependent on the AChE concentration from approximate to 0.04 x 10(-6) to 0.4 x 10(-6)m. An imprinting factor of 9.9 is obtained for the hybrid MIP, which is among the best values reported for protein imprinting. The dissociation constant characterizing the strength of the MIP-AChE binding is 4.2 x 10(-7)m indicating the dominant role of the PAS-Prop-SAM interaction, while the benefit of the MIP nanofilm covering the Prop-SAM layer is the effective suppression of the cross-reactivity toward competing proteins as compared with the Prop-SAM. The threefold selectivity gain provided by i) the shape-specific MIP filter, ii) the propidium-SAM, iii) signal generation only by the AChE bound to the nanofilm shows promise for assessing AChE activity levels in cerebrospinal fluid.