Redox-dyes for electrochemical challenges

biomers.net now offers modified oligonucleotides with methyleneblue and ferrocene at the 5’-end

During the past decade the development of oligonucleotide-based biosensors has become focus of research interest. A variety of target-binding oligonucleotides, so called aptamers, have been selected, showing great potential for biosensor application. These aptamer sequences interact specifically with target molecules such as nucleic acids, proteins or small organic compounds which in turn induce conformational change upon binding to the aptemere. For these applications biomers.net now offers the already well-established modifications Methyleneblue and Ferrocene. See below the exact chemical structure:

 

Figure 1: Chemical structure of Methyleneblue (a) and Ferrocene (b), connected by a 5C-spacer to the 5’ -end of the oligonucleotide.

 
biomers.net offers Ferrocene und Methyleneblue as 5´-modification for oligonucleotides up to 50 bases for the following prices: 

Prices are understood in addition to the base-price for the oligo and are only valid for electronic orders. Only 5´-modifications for up to 50 bases, HPLC-purification included, Vat may apply, for shipping costs please see pricelist

On the basis of this aptamer-technology several promising approaches are currently validated. The principle is described in the following figure (figure 2). The binding of the aptamere to its target can be visualised by optical or electrochemical methods. In case of a electrochemical sensor, target molecules are detected by voltammetric techniques. To this end, aptamer strands are immobilised on a gold surface by 3’ -thiol-function, for example. A redoxactive moiety is covalently attached to the 5’-end of the aptamer. In case of target-binding, conformational changes are induced affecting the electrochemical features of the redox moiety. 

 

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Figure 2: The mechanism of an e-sensor is shown. A redox-labelled aptamer (here: Methyleneblue) is immobilised on the surface of a gold electrode, taking up a special folding pattern. Binding of an added target oligonucleotide (green) results in a new conformation of the aptamer strand and accordingly a new orientation of the Methyleneblue to the gold surface. The distance of redox moiety to electrode directly influences electron transfer (red arrow), as measured by electrochemical methods.

For further details please contact us at: contact

References:

1. Ihara T, Maruo Y, Takenaka S, Takagi M. 1996. Ferrocene-oligonucleotide conjugates for electrochemical probing of DNA. Nucleic Acids Res 24. 4273.
2. Fan C, Plaxo KW, Heeger AJ. 2003. Electrochemical interrogation of conformational changes as a reagentless method for the sequence-specific detection of DNA. PNAS 100. 9134.
3. Lai RY, Lagally ET, Lee SH, Soh HT, Plaxo KW, Heeger AJ. 2006. Rapid, sequence-specific detection of unpurified PCR amplicons via a reusable, electrochemical sensor. PNAS 103. 4017.
4. Xiao Y, Lubin AA, Baker BR, Plaxco KW, Heeger AJ. 2006. Single-step electronic detection of femtomolar DNA by target-induced strand displacement in an electrode-bound duplex. PNAS 103. 16677.
5. Pänke O, Kirbs A, Lisdat F. 2007. Voltammetric detection of single base-pair mismatches and quantification of label-free target ssDNA using a competitive binding assay. Biosens Bioelektron 22, 2656.
6.  Lu Y, Li X, Zhang L, Yu P, Su L, Mao L. 2008. Aptamer-based electrochemical sensors with aptamer-complementary DNA oligonucleotides as probe. Anal Chem 80. 1883.