Gold electrode modified by self-assembled monolayers of thiols to determine DNA sequences hybridization

Abstract

Abstract. The process of immobilization of biological molecules is one of the most important steps in the construction of a biosensor. In the case of DNA, the way it exposes its bases can result in electrochemical signals to acceptable levels. The use of self-assembled monolayer that allows a connection to the gold thiol group and DNA binding to an aldehydic ligand resulted in the possibility of determining DNA hybridization. Immobilized single strand of DNA (ssDNA) from calf thymus pre-formed from alkanethiol film was formed by incubating a solution of 2-aminoethanothiol (Cys) followed by glutaraldehyde (Glu). Cyclic voltammetry (CV) was used to characterize the self-assembled monolayer on the gold electrode and, also, to study the immobilization of ssDNA probe and hybridization with the complementary sequence (target ssDNA). The ssDNA probe presents a well-defined oxidation peak at +0.158 V. When the hybridization occurs, this peak disappears which confirms the efficacy of the annealing and the DNA double helix performing without the presence of electroactive indicators. The use of SAM resulted in a stable immobilization of the ssDNA probe, enabling the hybridization detection without labels. This study represents a promising approach for molecular biosensor with sensible and reproducible results.

1-Amino-4-hydroxy-9,10-anthraquinone – An analogue of anthracycline anticancer drugs, interacts with DNA and induces apoptosis in human MDA-MB-231 breast adinocarcinoma cells: Evaluation of structure–activity relationship using computational, spectroscopic and biochemical studies

“…The concentration of experimental DNA solution was evaluated in terms of nucleotide by considering ε 260 =6600 M −1 cm −1 for ct DNA. Single-stranded DNA was prepared by using the method as described by Silva et al [35] .

Scheme 1 1-Amino-4-hydroxy-9,10-anthraquinone.

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A Compact Microelectrode Array Chip with Multiple Measuring Sites for Electrochemical Applications

“…Many applications of the electrodes involve modification of their surface using for instance deposition of self-assembled monolayers (SAMs) of thiols [20]. In such processes all the gold electrodes, including REs and CEs are modified simultaneously although only the IDEs should ideally be modified.…”

Fundamentals of Surface Modification

“…Trautner et al reported that a layer of mannose was covalently immobilized on silicon substrates. For this, they first attached carboxylic-acid-terminated monolayers via amidation, and then the mannose was used as the second layer and prepared layer by layer for modification [40], as shown in Fig. 4.14.…”