Cytosinederivatizedbis(2,2′-bithienyl)methanemolecularlyimprinted polymerforselectiverecognitionof6-thioguanine,anantitumordrug

A molecularlyimprintedpolymer(MIP)wasdesignedandsynthesizedtoserveasafunctionalmaterial
for selectiverecognitionof6-thioguanine(6TG),anantitumordrug.Forthat,thenewlysynthesized
functional monomer,cytosine-bis(2,2′-bithienyl)-(4-carboxyphenyl)methaneester(Cyt-S4),revealed
Watson–Crick typenucleobasepairingof6TG.FormationoftheCyt-S4and6TGcomplexofthe2:1
stoichiometry waspostulatedbasedontheDFTcalculationsattheB3LYP/3-21G(n) levelandexperi-
mentally confirmed by fluorescence titration.Themolecularlyimprintedpolymer(MIP) film wasde-
posited bypotentiodynamicelectropolymerizationonaPtdiskelectrodeaswellasonanAu-coatedglass
slide andonanAu-quartzcrystalresonator.Thestatisticalmodelofformationofthis film wassuc-
cessfully simulatedbymoleculardynamics.Completenessofthesubsequent6TGtemplateextraction
from MIPwasconfirmed bytheUV–visible spectroscopy.Animprintingfactorof2.9fortheMIP film was
determined bypiezoelectricmicrogravimetryusingECQM.Thedouble-layercapacityandalternating
current measurementsunder flow-injectionanalysis(FIA)conditionswereselectedtotransducethe6TG
recognition signalintothechangeofthedouble-layercapacitydependenceonthe6TGconcentrationin
solution fordifferentsupportingelectrolyteconcentrations.Detectabilityoftheresultingchemosensor
was10 mM 6TGforthe0.5MKFcarriersolutioninFIA.Selectivityofthechemosensorwithrespectto
common interferenceswashigh,e.g.,itexceeded130to2-amino-6-methylmercaptopurine,a6TGme-
tabolite.