Functional Electroactive Biomolecules

Bin, Xiaomin; Diakowski, Piotr M.; Kerman, Kağan; Kraatz, Heinz‐Bernhard

doi:10.1002/9780470583463.ch10

Cited by 1 publication

(2 citation statements)

References 147 publications

(125 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To expand the scope for application of these inherent capabilities of PNAs, structural modifications have been made to their backbone. Examples of such modifications span from replacing the natural bases with unnatural nucleobases to the introduction of fluorescent and/or electrochemical labels. − While the fluorophore-labeled PNAs have been widely used as diagnostic probes for nucleic acid sequences (e.g., PNA-FISH assay) − and for fluorescence-based cellular uptake studies aimed at antisense applications, ,,− electrochemical labels were introduced with the aim of using them as electrochemical biosensors. − ,− Ferrocene has been most widely employed for these purposes because of the stability of the ferrocenyl group, accessibility of a large library of its derivatives, and favorable electrochemical properties . Numerous examples of ferrocene conjugated PNA monomers and sequences are available in literature. ,,,,− However, the absence of any photophysical activity limits its scope in biosensing to electroactive probes.…”

Section: Introductionmentioning

confidence: 99%

“…Examples of such modifications span from replacing the natural bases with unnatural nucleobases to the introduction of fluorescent and/or electrochemical labels. − While the fluorophore-labeled PNAs have been widely used as diagnostic probes for nucleic acid sequences (e.g., PNA-FISH assay) − and for fluorescence-based cellular uptake studies aimed at antisense applications, ,,− electrochemical labels were introduced with the aim of using them as electrochemical biosensors. − ,− Ferrocene has been most widely employed for these purposes because of the stability of the ferrocenyl group, accessibility of a large library of its derivatives, and favorable electrochemical properties . Numerous examples of ferrocene conjugated PNA monomers and sequences are available in literature. ,,,,− However, the absence of any photophysical activity limits its scope in biosensing to electroactive probes. Recently, Gasser, Metzler-Nolte, and co-workers have emphasized the advantages of increasing the versatility of PNA conjugates by introducing multiple detection labels on the same PNA backbone. ,− They employed “click chemistry” to build different PNA monomers and oligomers incorporating ferrocene as electroactive unit ,, and have also demonstrated the feasibility of introducing multiple organometallic moieties into the same PNA oligomer using solid phase synthesis. ,, …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Electrochemiluminescent Monomers for Solid Support Syntheses of Ru(II)-PNA Bioconjugates: Multimodal Biosensing Tools with Enhanced Duplex Stability

et al. 2012

View full text Add to dashboard Cite

The feasibility of devising a solid support mediated approach to multimodal Ru(II)-peptide nucleic acid (PNA) oligomers is explored. Three Ru(II)-PNA-like monomers, [Ru(bpy)(2)(Cpp-L-PNA-OH)](2+) (M1), [Ru(phen)(2)(Cpp-L-PNA-OH)](2+) (M2), and [Ru(dppz)(2)(Cpp-L-PNA-OH)](2+) (M3) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dppz = dipyrido[3,2-a:2',3'-c]phenazine, Cpp-L-PNA-OH = [2-(N-9-fluorenylmethoxycarbonyl)aminoethyl]-N-[6-(2-(pyridin-2yl)pyrimidine-4-carboxamido)hexanoyl]-glycine), have been synthesized as building blocks for Ru(II)-PNA oligomers and characterized by IR and (1)H NMR spectroscopy, mass spectrometry, electrochemistry and elemental analysis. As a proof of principle, M1 was incorporated on the solid phase within the PNA sequences H-g-c-a-a-t-a-a-a-a-Lys-NH(2) (PNA1) and H-P-K-K-K-R-K-V-g-c-a-a-t-a-a-a-a-lys-NH(2) (PNA4) to give PNA2 (H-g-c-a-a-t-a-a-a-a-M1-lys-NH(2)) and PNA3 (H-P-K-K-K-R-K-V-g-c-a-a-t-a-a-a-a-M1-lys-NH(2)), respectively. The two Ru(II)-PNA oligomers, PNA2 and PNA3, displayed a metal to ligand charge transfer (MLCT) transition band centered around 445 nm and an emission maximum at about 680 nm following 450 nm excitation in aqueous solutions (10 mM PBS, pH 7.4). The absorption and emission response of the duplexes formed with the cDNA strand (DNA: 5'-T-T-T-T-T-T-T-A-T-T-G-C-T-T-T-3') showed no major variations, suggesting that the electronic properties of the Ru(II) complexes are largely unaffected by hybridization. The thermal stability of the PNA·DNA duplexes, as evaluated from UV melting experiments, is enhanced compared to the corresponding nonmetalated duplexes. The melting temperature (T(m)) was almost 8 °C higher for PNA2·DNA duplex, and 4 °C for PNA3·DNA duplex, with the stabilization attributed to the electrostatic interaction between the cationic residues (Ru(II) unit and positively charged lysine/arginine) and the polyanionic DNA backbone. In presence of tripropylamine (TPA) as co-reactant, PNA2, PNA3, PNA2·DNA and PNA3·DNA displayed strong electrochemiluminescence (ECL) signals even at submicromolar concentrations. Importantly, the combination of spectrochemical, thermal and ECL properties possessed by the Ru(II)-PNA sequences offer an elegant approach for the design of highly sensitive multimodal biosensing tools.

show abstract