β-Cyclodextrin-Based Ferrocene-Imprinted Gold Electrodes

Abstract

A new stepwise self-assembly procedure is described for the preparation of functional cyclodextrin-modified electrodes. The approach is based on the formation of alkanethiol/lipoylamide-beta-cyclodextrin monolayers with the thiol component responsible for blocking of the electrode surface and lipoylamide-beta-cyclodextrin molecules-for controlled opening of the access of the electroactive probe to the electrode. Functionalization of the electrode is achieved by means of a new cyclodextrin derivative-mono(6-deoxy-6-lipoylamide)-per-2,3,6-O-acetyl-beta-cyclodextrin-prepared in the peracetyl form and deacetylated directly on the electrode surface following the cyclodextrin self-assembly. The progress of deacetylation was monitored by the MALDI MS technique. Deacetylation caused opening of the active sites toward solution probes. The response toward ferrocene was found to be highly improved when ferrocene was added to the solution following self-assembly of cyclodextrin but prior to the thiol self-assembly step (imprinting method). The proposed synthesis and sequential monolayer formation scheme lead to well-organized and stable modified electrode surfaces with improved sensitivity toward solution species compared to other procedures of electrode modification with the cyclodextrin derivatives.

Recognition of Bile Acids at Cyclodextrin-Modified Gold Electrodes

“…For this purpose, we used LP-β-CD or LP-γ -CD as a membrane element and bile acids as guest species (Scheme 1). This is because LP-β-CD and LP-γ-CD have been known to form SAM [8][9][10][11] and because bile acids are known as excellent guests for CD derivatives. [16][17][18][19] First, we determined the binding constants (Ksoln) of γ-CD with bile acids in homogeneous aqueous solution, employing a spectral displacement method 20 using phenolphthalein (PP) as a dye species.…”

“…4 Thus, several researchers have already reported the formation of selfassembled membranes (SAM) of CDs. [4][5][6][7][8][9][10] The evaluations of the molecular recognition properties of the resulting CD SAMs have been achieved with electrochemical measurements, [5][6][7][8][9][10][11][12] scanning probe microscopy, 13 surface-enhanced Raman scattering, 14 and quartz crystal microbalance. 15 Regarding sensor applications, electrochemical responses of some marker compounds (electrochemically active species existing in a bulk solution phase) were often used as signal transduction agents because of the ease in quantitative analyses for observed electrochemical responses.…”

“…15 Regarding sensor applications, electrochemical responses of some marker compounds (electrochemically active species existing in a bulk solution phase) were often used as signal transduction agents because of the ease in quantitative analyses for observed electrochemical responses. For this purpose, ferrocene [6][7][8][9][10][11] and quinone 12,15 derivatives have been used for realizing favorable signal transduction in voltammetric responses for the molecular recognition at the CD SAMs.…”

Catalytic Au Electrodes Based on SAMs of per(6‐deoxy‐6‐thio‐2,3‐di‐O‐methyl)‐β‐cyclodextrin

“…In a recent paper, we presented a three-step sequential self-assembly procedure applied to prepare gold electrodes modified with b-CD [19] and responsive to ibuprofen. The ibuprofen presence in solution led to the decrease of a ferrocene anodic cyclic voltammetry (CV) peak since, due to larger affinity to b-CD, the ibuprofen molecule substituted the ferrocene molecule in the b-CD macrocyclic cavity.…”

On the Role of Electrostatic Interactions in the Enantioselective Recognition of Phenylalanine in Molecularly Imprinted Polymers Incorporating β-Cyclodextrin

“…As a promising alternative approach, several recent studies report the use of cyclodextrin (CD) derived structures as functional monomers for molecular imprinting in aqueous environments, where the hydrophobic binding pocket of the CD is utilized to recognize water soluble structures containing hydrophobic moieties. [8][9][10][11][12] In work by our group, 13 terpolymers selective for either of the enantiomers of phenylalanine (1) were developed using the functional monomers bisacryloyl -CD (2) and 2-acryloylamido-2-methyl-1-propane sulfonic acid (AMPSA, 3), and the cross-linking agent N,N 0 -diacryloylpiperazine (DAP, 4), Figure 1. The roles of the hydrophobic interacting CD and the electrostatic interacting sulfonic acid monomers were examined with chromatographic analyses.…”