Monolayers electrochemical detection

Amplified electrochemical detection of DNA in monolayer assemblies was accomplished by the conjugation of bioelectrocatalytic transformations to the DNA recognition events. This was exemplified with the amplified electrochemical analysis of M13 phage DNA (Fig. 12.20a).75 A capturing nucleic acid, (20), complementary to... 

Malem, E, and Mandler, D. Self-assembled monolayers in electroanalytical chemistry -application of to-mercapto carboxylic-acid monolayers for the electrochemical detection of dopamine in the presence of a high-concentration of ascorbic acid. Anal. Chem. 1993, 65, 37-41. 

The characteristic electrochemical behavior of enzyme, protein and Upid monolayers adhered to SAMs derived from thiols on gold surfaces may be applied to the development of biosensors. The gold electrodes resulting from incorporation of monensin (203) and vaUnomycin (204) into bilayers, consisting of the SAMs of aUsanethiol covered by a Upid monolayer, have high sensitivity for monovalent ions . A gold electrode with a SAM of a modified /3-cyclodextrin was proposed for electrochemical detection of organic compounds . 

Ferrocenylated ODNs were first immobilized in a self-assembled redox-active monolayer on Au electrodes by Letsinger and co-workers.Upon hybridization of a complementary strand, the electrochemical potential of the ferrocene changes. In addition to applications as electrochemical DNA sensors, such self-assembled DNA monolayers with electro-active groups may provide information on the mechanism of electron transfer through DNA, and indirectly also on molecular mobility within short stretches of DNA. " We have recently extended this idea by the use of immobilized metallocene-labeled PNA on Au electrodes. Because PNA is an uncharged molecule, a surface with improved properties forms, and electrochemical detection, also of single mismatches, is facilitated. 

Flink. S. Boukamp, B.A. van den Berg. A. van Veggel. F.C.J.M. Reinhoudt. D.N. Electrochemical detection of electrochemically inactive cations by self-assembled monolayers of crown ethers. J. Am. Chem. Soc. 1998, 120. 4652-4657. 

D. Ozkan, A. Erdem, P. Kara, K. Kerman, J. J. Gooding, P. E. Nielsen, and M. Ozsoz, Electrochemical detection of hybridization using peptide nucleic acids and methylene blue on self-assembled alkanethiol monolayer modified gold electrodes, Electrochem. Comm. 4[10], 796-802 [2002]. 

Fig. 1.1 Schematic representation of the eSensor DNA Detection System. A self-assembled monolayer is generated on a gold electrode. For electrochemical detection to occur across the monolayer, two hybridization events must occur the first between the capture probe (shown in black perpendicular to the electrode) and the target (for example, human papillomavirus DNA, shown in gray), and the second between an adjacent region of the target and ferrocene labeled signal probe (shown in black parallel to the monolayer) [106].

Lie, L. H., Mirkin, M. V, Hakkarainen, S., Houlton, A., Horrocks, B. R. Electrochemical detection of lateral charge transport in metal complex-DNA monolayers synthesized on Si(lll) electrodes. J Electroanal Chem 2007, 603, 67-80. 

Campuzano S, Kuralay F, Jesus Lobo-Castanon M, Bartosik M, Vyavahare K, Palecek E, Haake DA, Wang J (2011) Ternary monolayers as DNA recognition interfaces for direct and sensitive electrochemical detection in untreated clinical samples. Biosens Bioelectron 26 3577-3583... 

Nitrophenyl groups covalently bonded to classy carbon and graphite surfaces have been detected and characterized by unenhanced Raman spectroscopy in combination with voltammetry and XPS [4.292]. Difference spectra from glassy carbon with and without nitrophenyl modification contained several Raman bands from the nitrophenyl group with a comparatively large signal-to-noise ratio (Fig. 4.58). Electrochemical modification of the adsorbed monolayer was observed spectrally, because this led to clear changes in the Raman spectrum. 

---