title: Acetylcholine detection at micromolar concentrations with the use of an artificial receptor-based fluorescence switch.
abstract: An inclusion complex between water-soluble p-sulfocalix[n]arene (Cn, n=4, 6, 8) and the chromophore trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium-p-toluenesulfonate (D) formed the basis for a highly sensitive sensor for the selective detection of neurotransmitter acetylcholine (ACh). Formation of the [Cn.D] complex (Ka=approximately 10(5) M(-1)) was accompanied by a drastic increase (up to 20-60-fold) in the chromophore relative quantum yield and by a large hypsochromic shift of the emission band maximum. The observed optical effects are fully reversible: ACh displaces the chromophore molecules from the calixarene cavity as shown by the reappearance of the free chromophore emission band. Formation and dissociation of the complex were studied by fluorescence, 1H NMR, and UV-vis absorption spectroscopies. The [Cn.D] complex is capable of sensing ACh selectively in solution at sub-micromolar concentrations. Immobilization of monocarboxyl p-sulfocalix[4]arene (C4m) on an oxide-containing silicon surface is in keeping with its properties, such as chromophore binding and the ability of the immobilized inclusion complex to detect ACh. The unique [Cn.D] complex optical switching paves the way for application in ACh imaging and optoelectronic sensing.
authors.affiliation: The Chemistry Institute and the Farkas Center for Light Induced Processes and Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Nina
authors.initials: N
authors.lastname: Korbakov
authors.forename: Peter
authors.initials: P
authors.lastname: Timmerman
authors.forename: Nina
authors.initials: N
authors.lastname: Lidich
authors.forename: Benayahu
authors.initials: B
authors.lastname: Urbach
authors.forename: Amir
authors.initials: A
authors.lastname: Sa'ar
authors.forename: Shlomo
authors.initials: S
authors.lastname: Yitzchaik
mesh_terms: D000109:Acetylcholine / Q000032:analysis*; D001557:Benzenesulfonates / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D047250:Calixarenes / Q000737:chemistry*; D015394:Molecular Structure; D011726:Pyridinium Compounds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties
chemical_list: D001557:Benzenesulfonates; D011726:Pyridinium Compounds; D012996:Solutions; C528792:trans-4-(4-(dimethylamino)styryl)-1-methylpyridinium-p-toluenesulfonate; D047250:Calixarenes; D000109:Acetylcholine