Tetrathiafulvalene thiolated derivatives self-assembled monolayers as platforms for the construction of electrochemical biosensors

The possibility of using TTF-derivatized SAMs as platforms for the construction of electrochemical biosensors is explored. The properties and characteristics of the electroactive SAMs formed with 4-mercaptotetrathiafulvalene (HSTTF) and 4-(mercapto-ethan-2-tiliol)-tetrathiafulvalene (HSC2STTF), and their ability to promote the electron transfer between the active center of the immobilized enzyme, HRP, and the electrode surface is evaluated. Calculations from electrochemical impedance spectroscopy data showed a microarray behavior for HSC2STTF-SAMs. However, semi-infinite diffusion was not obtained for HSTTF-SAMs. The slope value of the H2O2 Calibration plot obtained by flow-injection with amperometric detection at 0.00 V was more than one order Of Magnitude higher with the HSTTF design, which is attributed to the larger number of TTF moieties present at the electrode surface. The performance of the bioelectrocatalytic integrated devices is shown to be very dependent on the molecular structure of the TTF derivative. (c) 2005 Elsevier B.V. All rights reserved.